Audio / video cable Overview <br> video cable, referred to as a video line, and the video cable connector of two parts, wherein: the video cable is a 75-ohm characteristic impedance (ohms) of the coaxial shielded cable, common specifications in a line The diameter is divided into two types, namely -3 and -5. There are two kinds of single-core wire and multi-core wire according to the core wire. The common specifications of the connector are divided into two types: the crimping joint and the welding joint according to the cable end connection mode. The connection method is divided into BNC (commonly known as card head) and RCA (commonly known as lotus head).
The audio cable, referred to as the audio cable, is composed of an audio cable and a connector. The audio cable is generally a double-core shielded cable. The common connector is RCA (commonly known as lotus head), XLR (commonly known as card head), and TRS. JACKS (commonly known as the pen head).
Video cable
The video line is an important part of the video system of the TV broadcast control room. The quality of the production directly affects the technical indicators of the video channel. The poor quality video line may cause the signal to be reversed, the signal is seriously attenuated, the device is not synchronized, and even the signal is interrupted. In addition to a small number of control signal lines in the video system, signals such as program signals, synchronization signals, and key signals are transmitted by video lines , and thus problems in the video lines are one of the common sources of failures in equipment and system failure.
In the process of making a video cable , you must first select the correct video cable and connector. The cable should first be noted for its nominal impedance. A cable with a characteristic impedance of 50 Ω is similar in appearance to the video cable and must not be confused. In addition, attention should be paid to the occurrence of oxidation of the cable or connector. The cable or connector should be scrapped or disposed of as appropriate. Otherwise, the oxide will cause solder joints to be soldered, resulting in severe signal attenuation or even interruption. There are individual manufacturers in the market to cut corners, and the production of video lines does not meet the specifications, such as: sparse shielding, wire diameter is not standard, etc., also pay attention when buying. In the selection of the connector, try to meet the needs of the equipment, avoid using the adapter, and the specifications should be used according to the specifications of the cable.
Secondly, good crimp quality or weld quality must be guaranteed. The use of crimping joints is very strict on the wire diameter and crimping process of the various layers of the cable. It is easier to make on the surface, but if you pay little attention, it may be connected. If you plug it frequently, the reliability will be lower. Should avoid using this type of joints as much as possible. When it is necessary to use it, it is best to press it after welding, and at the same time, avoid using force on the cable when plugging and unplugging. Relatively speaking, the welding type joints have lower requirements on the process, but it is still necessary to pay attention to the specifications of the joints to be consistent with the cable specifications. The welding requirements are the same as those for welding common electronic circuit boards. The solder joints should be smooth and flat without any solder joints. .
Finally, you must check for open or short circuits. Whenever a video cable is made , no matter what the connector or length, it is necessary to check with a multimeter to determine that there is no open circuit or short circuit.
Audio cable
The audio line is more complicated than the video line . In addition to the above three considerations, there is also a problem of balanced and unbalanced connection.
The so-called balanced connection method is a method of connecting a pair of balanced signals by using two signal lines. Since the interference levels of the two signal lines are the same, the phases are opposite, and finally the interference is cancelled. Due to the low frequency range of the audio, it is susceptible to interference under long-distance transmission. Therefore, the balanced connection is an interference-free connection method, which is most common in audio connections of professional equipment. The two-core shielded cable is also used as an audio connection cable in the connection line of the household appliance. However, it transmits the left and right channels, which are two signals and are not balanced.
Unbalanced connection is a connection method that uses only one signal line to transmit signals. Since this connection is susceptible to interference, it is generally used only in household appliances or in some cases where the requirements are low.
The specific connection method is taken as an example of XLR connector: 1. Balance connection: 1 pin connection shield, 2 pin connection + end (also called hot end), 3 pin connection end (also called cold end); 2. Unbalanced connection Method: 1 pin and 3 pin are connected to shield, 2 pin is connected to + end (signal end).
The choice of connection is generally based on the specific requirements of the interface of the device. You can use the balanced connection method as much as possible. When connecting, be sure to read the instructions on the panel first. It is best to read the instructions on the instruction manual and Claim. In some cases, it may be encountered that the device interface at one end is a balanced interface, and the device at the other end is an unbalanced interface. In the case where the requirements are not very strict, only the balanced connection method is used at the balanced end, and the unbalanced connection is used unbalanced. Law, pay attention to the corresponding foot can be. In the case of strict requirements, it is necessary to use a conversion circuit to turn the balance into an imbalance or to turn the imbalance into a balance.
Line code
In a broadcast control room, the number of video and audio cables connected to each signal is quite large. At the same time, because the location is very concentrated, if you do not encode each cable, it will bring extreme maintenance to the future. Great inconvenience. The method is very simple. Before making the connector, you can put the line code on the two ends of the AV cable according to the pre-programmed number. The principle of coding is simple and intuitive. Encoding that is too complicated or too abstract is also not easy to maintain.
It is recommended to use a combination of letters and numbers, such as: VD101 represents the first output (01) of the video (V) splitter (D) No. 1 (1). Through such a set of codes, it is explained that: 1. Signal property: video signal; 2. Signal source: video distributor; 3 device number: No. 1 machine; 4. Port position: No. 1 output port.
The letters can be selected from commonly used English abbreviations, Chinese pinyin or other easy-to-understand letter combinations. The common English abbreviations are listed below for reference.
Abbreviation original meaning
V VIDEO video
A AUDIO audio
B BBLACK BURST black field (synchronous signal)
P PLAYER
R RECORDER deck
D DISTRIBUTER dispenser
M MONITOR monitor
CG CHARACTER GENERATOR captioning machine
O OPTICAL RECEIVER Optical Receiver
T TBC time base corrector
No matter what kind of coding method is adopted, it is planned in advance to form a standard, and at least one coding method is uniformly used in one system. After completing the system, you must keep the line code table in a safe place for future reference.
Audio / video cable Overview <br> video cable, referred to as a video line, and the video cable connector of two parts, wherein: the video cable is a 75-ohm characteristic impedance (ohms) of the coaxial shielded cable, common specifications in a line The diameter is divided into two types, namely -3 and -5. There are two kinds of single-core wire and multi-core wire according to the core wire. The common specifications of the connector are divided into two types: the crimping joint and the welding joint according to the cable end connection mode. The connection method is divided into BNC (commonly known as card head) and RCA (commonly known as lotus head).
The audio cable, referred to as the audio cable, is composed of an audio cable and a connector. The audio cable is generally a double-core shielded cable. The common connector is RCA (commonly known as lotus head), XLR (commonly known as card head), and TRS. JACKS (commonly known as the pen head).
Video cable
The video line is an important part of the video system of the TV broadcast control room. The quality of the production directly affects the technical indicators of the video channel. The poor quality video line may cause the signal to be reversed, the signal is seriously attenuated, the device is not synchronized, and even the signal is interrupted. In addition to a small number of control signal lines in the video system, signals such as program signals, synchronization signals, and key signals are transmitted by video lines , and thus problems in the video lines are one of the common sources of failures in equipment and system failure.
In the process of making a video cable , you must first select the correct video cable and connector. The cable should first be noted for its nominal impedance. A cable with a characteristic impedance of 50 Ω is similar in appearance to the video cable and must not be confused. In addition, attention should be paid to the occurrence of oxidation of the cable or connector. The cable or connector should be scrapped or disposed of as appropriate. Otherwise, the oxide will cause solder joints to be soldered, resulting in severe signal attenuation or even interruption. There are individual manufacturers in the market to cut corners, and the production of video lines does not meet the specifications, such as: sparse shielding, wire diameter is not standard, etc., also pay attention when buying. In the selection of the connector, try to meet the needs of the equipment, avoid using the adapter, and the specifications should be used according to the specifications of the cable.
Secondly, good crimp quality or weld quality must be guaranteed. The use of crimping joints is very strict on the wire diameter and crimping process of the various layers of the cable. It is easier to make on the surface, but if you pay little attention, it may be connected. If you plug it frequently, the reliability will be lower. Should avoid using this type of joints as much as possible. When it is necessary to use it, it is best to press it after welding, and at the same time, avoid using force on the cable when plugging and unplugging. Relatively speaking, the welding type joints have lower requirements on the process, but it is still necessary to pay attention to the specifications of the joints to be consistent with the cable specifications. The welding requirements are the same as those for welding common electronic circuit boards. The solder joints should be smooth and flat without any solder joints. .
Finally, you must check for open or short circuits. Whenever a video cable is made , no matter what the connector or length, it is necessary to check with a multimeter to determine that there is no open circuit or short circuit.
Audio cable
The audio line is more complicated than the video line . In addition to the above three considerations, there is also a problem of balanced and unbalanced connection.
The so-called balanced connection method is a method of connecting a pair of balanced signals by using two signal lines. Since the interference levels of the two signal lines are the same, the phases are opposite, and finally the interference is cancelled. Due to the low frequency range of the audio, it is susceptible to interference under long-distance transmission. Therefore, the balanced connection is an interference-free connection method, which is most common in audio connections of professional equipment. The two-core shielded cable is also used as an audio connection cable in the connection line of the household appliance. However, it transmits the left and right channels, which are two signals and are not balanced.
Unbalanced connection is a connection method that uses only one signal line to transmit signals. Since this connection is susceptible to interference, it is generally used only in household appliances or in some cases where the requirements are low.
The specific connection method is taken as an example of XLR connector: 1. Balance connection: 1 pin connection shield, 2 pin connection + end (also called hot end), 3 pin connection end (also called cold end); 2. Unbalanced connection Method: 1 pin and 3 pin are connected to shield, 2 pin is connected to + end (signal end).
The choice of connection is generally based on the specific requirements of the interface of the device. You can use the balanced connection method as much as possible. When connecting, be sure to read the instructions on the panel first. It is best to read the instructions on the instruction manual and Claim. In some cases, it may be encountered that the device interface at one end is a balanced interface, and the device at the other end is an unbalanced interface. In the case where the requirements are not very strict, only the balanced connection method is used at the balanced end, and the unbalanced connection is used unbalanced. Law, pay attention to the corresponding foot can be. In the case of strict requirements, it is necessary to use a conversion circuit to turn the balance into an imbalance or to turn the imbalance into a balance.
Line code
In a broadcast control room, the number of video and audio cables connected to each signal is quite large. At the same time, because the location is very concentrated, if you do not encode each cable, it will bring extreme maintenance to the future. Great inconvenience. The method is very simple. Before making the connector, you can put the line code on the two ends of the AV cable according to the pre-programmed number. The principle of coding is simple and intuitive. Encoding that is too complicated or too abstract is also not easy to maintain.
It is recommended to use a combination of letters and numbers, such as: VD101 represents the first output (01) of the video (V) splitter (D) No. 1 (1). Through such a set of codes, it is explained that: 1. Signal property: video signal; 2. Signal source: video distributor; 3 device number: No. 1 machine; 4. Port position: No. 1 output port.
The letters can be selected from commonly used English abbreviations, Chinese pinyin or other easy-to-understand letter combinations. The common English abbreviations are listed below for reference.
Abbreviation original meaning
V VIDEO video
A AUDIO audio
B BBLACK BURST black field (synchronous signal)
P PLAYER
R RECORDER deck
D DISTRIBUTER dispenser
M MONITOR monitor
CG CHARACTER GENERATOR captioning machine
O OPTICAL RECEIVER Optical Receiver
T TBC time base corrector
No matter what kind of coding method is adopted, it is planned in advance to form a standard, and at least one coding method is uniformly used in one system. After completing the system, you must keep the line code table in a safe place for future reference.
Audio / video cable Overview <br> video cable, referred to as a video line, and the video cable connector of two parts, wherein: the video cable is a 75-ohm characteristic impedance (ohms) of the coaxial shielded cable, common specifications in a line The diameter is divided into two types, namely -3 and -5. There are two kinds of single-core wire and multi-core wire according to the core wire. The common specifications of the connector are divided into two types: the crimping joint and the welding joint according to the cable end connection mode. The connection method is divided into BNC (commonly known as card head) and RCA (commonly known as lotus head).
The audio cable, referred to as the audio cable, is composed of an audio cable and a connector. The audio cable is generally a double-core shielded cable. The common connector is RCA (commonly known as lotus head), XLR (commonly known as card head), and TRS. JACKS (commonly known as the pen head).
Video cable
The video line is an important part of the video system of the TV broadcast control room. The quality of the production directly affects the technical indicators of the video channel. The poor quality video line may cause the signal to be reversed, the signal is seriously attenuated, the device is not synchronized, and even the signal is interrupted. In addition to a small number of control signal lines in the video system, signals such as program signals, synchronization signals, and key signals are transmitted by video lines , and thus problems in the video lines are one of the common sources of failures in equipment and system failure.
In the process of making a video cable , you must first select the correct video cable and connector. The cable should first be noted for its nominal impedance. A cable with a characteristic impedance of 50 Ω is similar in appearance to the video cable and must not be confused. In addition, attention should be paid to the occurrence of oxidation of the cable or connector. The cable or connector should be scrapped or disposed of as appropriate. Otherwise, the oxide will cause solder joints to be soldered, resulting in severe signal attenuation or even interruption. There are individual manufacturers in the market to cut corners, and the production of video lines does not meet the specifications, such as: sparse shielding, wire diameter is not standard, etc., also pay attention when buying. In the selection of the connector, try to meet the needs of the equipment, avoid using the adapter, and the specifications should be used according to the specifications of the cable.
Secondly, good crimp quality or weld quality must be guaranteed. The use of crimping joints is very strict on the wire diameter and crimping process of the various layers of the cable. It is easier to make on the surface, but if you pay little attention, it may be connected. If you plug it frequently, the reliability will be lower. Should avoid using this type of joints as much as possible. When it is necessary to use it, it is best to press it after welding, and at the same time, avoid using force on the cable when plugging and unplugging. Relatively speaking, the welding type joints have lower requirements on the process, but it is still necessary to pay attention to the specifications of the joints to be consistent with the cable specifications. The welding requirements are the same as those for welding common electronic circuit boards. The solder joints should be smooth and flat without any solder joints. .
Finally, you must check for open or short circuits. Whenever a video cable is made , no matter what the connector or length, it is necessary to check with a multimeter to determine that there is no open circuit or short circuit.
Audio cable
The audio line is more complicated than the video line . In addition to the above three considerations, there is also a problem of balanced and unbalanced connection.
The so-called balanced connection method is a method of connecting a pair of balanced signals by using two signal lines. Since the interference levels of the two signal lines are the same, the phases are opposite, and finally the interference is cancelled. Due to the low frequency range of the audio, it is susceptible to interference under long-distance transmission. Therefore, the balanced connection is an interference-free connection method, which is most common in audio connections of professional equipment. The two-core shielded cable is also used as an audio connection cable in the connection line of the household appliance. However, it transmits the left and right channels, which are two signals and are not balanced.
Unbalanced connection is a connection method that uses only one signal line to transmit signals. Since this connection is susceptible to interference, it is generally used only in household appliances or in some cases where the requirements are low.
The specific connection method is taken as an example of XLR connector: 1. Balance connection: 1 pin connection shield, 2 pin connection + end (also called hot end), 3 pin connection end (also called cold end); 2. Unbalanced connection Method: 1 pin and 3 pin are connected to shield, 2 pin is connected to + end (signal end).
The choice of connection is generally based on the specific requirements of the interface of the device. You can use the balanced connection method as much as possible. When connecting, be sure to read the instructions on the panel first. It is best to read the instructions on the instruction manual and Claim. In some cases, it may be encountered that the device interface at one end is a balanced interface, and the device at the other end is an unbalanced interface. In the case where the requirements are not very strict, only the balanced connection method is used at the balanced end, and the unbalanced connection is used unbalanced. Law, pay attention to the corresponding foot can be. In the case of strict requirements, it is necessary to use a conversion circuit to turn the balance into an imbalance or to turn the imbalance into a balance.
Line code
In a broadcast control room, the number of video and audio cables connected to each signal is quite large. At the same time, because the location is very concentrated, if you do not encode each cable, it will bring extreme maintenance to the future. Great inconvenience. The method is very simple. Before making the connector, you can put the line code on the two ends of the AV cable according to the pre-programmed number. The principle of coding is simple and intuitive. Encoding that is too complicated or too abstract is also not easy to maintain.
It is recommended to use a combination of letters and numbers, such as: VD101 represents the first output (01) of the video (V) splitter (D) No. 1 (1). Through such a set of codes, it is explained that: 1. Signal property: video signal; 2. Signal source: video distributor; 3 device number: No. 1 machine; 4. Port position: No. 1 output port.
The letters can be selected from commonly used English abbreviations, Chinese pinyin or other easy-to-understand letter combinations. The common English abbreviations are listed below for reference.
Abbreviation original meaning
V VIDEO video
A AUDIO audio
B BBLACK BURST black field (synchronous signal)
P PLAYER
R RECORDER deck
D DISTRIBUTER dispenser
M MONITOR monitor
CG CHARACTER GENERATOR captioning machine
O OPTICAL RECEIVER Optical Receiver
T TBC time base corrector
No matter what kind of coding method is adopted, it is planned in advance to form a standard, and at least one coding method is uniformly used in one system. After completing the system, you must keep the line code table in a safe place for future reference.
The audio cable, referred to as the audio cable, is composed of an audio cable and a connector. The audio cable is generally a double-core shielded cable. The common connector is RCA (commonly known as lotus head), XLR (commonly known as card head), and TRS. JACKS (commonly known as the pen head).
Video cable
The video line is an important part of the video system of the TV broadcast control room. The quality of the production directly affects the technical indicators of the video channel. The poor quality video line may cause the signal to be reversed, the signal is seriously attenuated, the device is not synchronized, and even the signal is interrupted. In addition to a small number of control signal lines in the video system, signals such as program signals, synchronization signals, and key signals are transmitted by video lines , and thus problems in the video lines are one of the common sources of failures in equipment and system failure.
In the process of making a video cable , you must first select the correct video cable and connector. The cable should first be noted for its nominal impedance. A cable with a characteristic impedance of 50 Ω is similar in appearance to the video cable and must not be confused. In addition, attention should be paid to the occurrence of oxidation of the cable or connector. The cable or connector should be scrapped or disposed of as appropriate. Otherwise, the oxide will cause solder joints to be soldered, resulting in severe signal attenuation or even interruption. There are individual manufacturers in the market to cut corners, and the production of video lines does not meet the specifications, such as: sparse shielding, wire diameter is not standard, etc., also pay attention when buying. In the selection of the connector, try to meet the needs of the equipment, avoid using the adapter, and the specifications should be used according to the specifications of the cable.
Secondly, good crimp quality or weld quality must be guaranteed. The use of crimping joints is very strict on the wire diameter and crimping process of the various layers of the cable. It is easier to make on the surface, but if you pay little attention, it may be connected. If you plug it frequently, the reliability will be lower. Should avoid using this type of joints as much as possible. When it is necessary to use it, it is best to press it after welding, and at the same time, avoid using force on the cable when plugging and unplugging. Relatively speaking, the welding type joints have lower requirements on the process, but it is still necessary to pay attention to the specifications of the joints to be consistent with the cable specifications. The welding requirements are the same as those for welding common electronic circuit boards. The solder joints should be smooth and flat without any solder joints. .
Finally, you must check for open or short circuits. Whenever a video cable is made , no matter what the connector or length, it is necessary to check with a multimeter to determine that there is no open circuit or short circuit.
Audio cable
The audio line is more complicated than the video line . In addition to the above three considerations, there is also a problem of balanced and unbalanced connection.
The so-called balanced connection method is a method of connecting a pair of balanced signals by using two signal lines. Since the interference levels of the two signal lines are the same, the phases are opposite, and finally the interference is cancelled. Due to the low frequency range of the audio, it is susceptible to interference under long-distance transmission. Therefore, the balanced connection is an interference-free connection method, which is most common in audio connections of professional equipment. The two-core shielded cable is also used as an audio connection cable in the connection line of the household appliance. However, it transmits the left and right channels, which are two signals and are not balanced.
Unbalanced connection is a connection method that uses only one signal line to transmit signals. Since this connection is susceptible to interference, it is generally used only in household appliances or in some cases where the requirements are low.
The specific connection method is taken as an example of XLR connector: 1. Balance connection: 1 pin connection shield, 2 pin connection + end (also called hot end), 3 pin connection end (also called cold end); 2. Unbalanced connection Method: 1 pin and 3 pin are connected to shield, 2 pin is connected to + end (signal end).
The choice of connection is generally based on the specific requirements of the interface of the device. You can use the balanced connection method as much as possible. When connecting, be sure to read the instructions on the panel first. It is best to read the instructions on the instruction manual and Claim. In some cases, it may be encountered that the device interface at one end is a balanced interface, and the device at the other end is an unbalanced interface. In the case where the requirements are not very strict, only the balanced connection method is used at the balanced end, and the unbalanced connection is used unbalanced. Law, pay attention to the corresponding foot can be. In the case of strict requirements, it is necessary to use a conversion circuit to turn the balance into an imbalance or to turn the imbalance into a balance.
Line code
In a broadcast control room, the number of video and audio cables connected to each signal is quite large. At the same time, because the location is very concentrated, if you do not encode each cable, it will bring extreme maintenance to the future. Great inconvenience. The method is very simple. Before making the connector, you can put the line code on the two ends of the AV cable according to the pre-programmed number. The principle of coding is simple and intuitive. Encoding that is too complicated or too abstract is also not easy to maintain.
It is recommended to use a combination of letters and numbers, such as: VD101 represents the first output (01) of the video (V) splitter (D) No. 1 (1). Through such a set of codes, it is explained that: 1. Signal property: video signal; 2. Signal source: video distributor; 3 device number: No. 1 machine; 4. Port position: No. 1 output port.
The letters can be selected from commonly used English abbreviations, Chinese pinyin or other easy-to-understand letter combinations. The common English abbreviations are listed below for reference.
Abbreviation original meaning
V VIDEO video
A AUDIO audio
B BBLACK BURST black field (synchronous signal)
P PLAYER
R RECORDER deck
D DISTRIBUTER dispenser
M MONITOR monitor
CG CHARACTER GENERATOR captioning machine
O OPTICAL RECEIVER Optical Receiver
T TBC time base corrector
No matter what kind of coding method is adopted, it is planned in advance to form a standard, and at least one coding method is uniformly used in one system. After completing the system, you must keep the line code table in a safe place for future reference.
Audio / video cable Overview <br> video cable, referred to as a video line, and the video cable connector of two parts, wherein: the video cable is a 75-ohm characteristic impedance (ohms) of the coaxial shielded cable, common specifications in a line The diameter is divided into two types, namely -3 and -5. There are two kinds of single-core wire and multi-core wire according to the core wire. The common specifications of the connector are divided into two types: the crimping joint and the welding joint according to the cable end connection mode. The connection method is divided into BNC (commonly known as card head) and RCA (commonly known as lotus head).
The audio cable, referred to as the audio cable, is composed of an audio cable and a connector. The audio cable is generally a double-core shielded cable. The common connector is RCA (commonly known as lotus head), XLR (commonly known as card head), and TRS. JACKS (commonly known as the pen head).
Video cable
The video line is an important part of the video system of the TV broadcast control room. The quality of the production directly affects the technical indicators of the video channel. The poor quality video line may cause the signal to be reversed, the signal is seriously attenuated, the device is not synchronized, and even the signal is interrupted. In addition to a small number of control signal lines in the video system, signals such as program signals, synchronization signals, and key signals are transmitted by video lines , and thus problems in the video lines are one of the common sources of failures in equipment and system failure.
In the process of making a video cable , you must first select the correct video cable and connector. The cable should first be noted for its nominal impedance. A cable with a characteristic impedance of 50 Ω is similar in appearance to the video cable and must not be confused. In addition, attention should be paid to the occurrence of oxidation of the cable or connector. The cable or connector should be scrapped or disposed of as appropriate. Otherwise, the oxide will cause solder joints to be soldered, resulting in severe signal attenuation or even interruption. There are individual manufacturers in the market to cut corners, and the production of video lines does not meet the specifications, such as: sparse shielding, wire diameter is not standard, etc., also pay attention when buying. In the selection of the connector, try to meet the needs of the equipment, avoid using the adapter, and the specifications should be used according to the specifications of the cable.
Secondly, good crimp quality or weld quality must be guaranteed. The use of crimping joints is very strict on the wire diameter and crimping process of the various layers of the cable. It is easier to make on the surface, but if you pay little attention, it may be connected. If you plug it frequently, the reliability will be lower. Should avoid using this type of joints as much as possible. When it is necessary to use it, it is best to press it after welding, and at the same time, avoid using force on the cable when plugging and unplugging. Relatively speaking, the welding type joints have lower requirements on the process, but it is still necessary to pay attention to the specifications of the joints to be consistent with the cable specifications. The welding requirements are the same as those for welding common electronic circuit boards. The solder joints should be smooth and flat without any solder joints. .
Finally, you must check for open or short circuits. Whenever a video cable is made , no matter what the connector or length, it is necessary to check with a multimeter to determine that there is no open circuit or short circuit.
Audio cable
The audio line is more complicated than the video line . In addition to the above three considerations, there is also a problem of balanced and unbalanced connection.
The so-called balanced connection method is a method of connecting a pair of balanced signals by using two signal lines. Since the interference levels of the two signal lines are the same, the phases are opposite, and finally the interference is cancelled. Due to the low frequency range of the audio, it is susceptible to interference under long-distance transmission. Therefore, the balanced connection is an interference-free connection method, which is most common in audio connections of professional equipment. The two-core shielded cable is also used as an audio connection cable in the connection line of the household appliance. However, it transmits the left and right channels, which are two signals and are not balanced.
Unbalanced connection is a connection method that uses only one signal line to transmit signals. Since this connection is susceptible to interference, it is generally used only in household appliances or in some cases where the requirements are low.
The specific connection method is taken as an example of XLR connector: 1. Balance connection: 1 pin connection shield, 2 pin connection + end (also called hot end), 3 pin connection end (also called cold end); 2. Unbalanced connection Method: 1 pin and 3 pin are connected to shield, 2 pin is connected to + end (signal end).
The choice of connection is generally based on the specific requirements of the interface of the device. You can use the balanced connection method as much as possible. When connecting, be sure to read the instructions on the panel first. It is best to read the instructions on the instruction manual and Claim. In some cases, it may be encountered that the device interface at one end is a balanced interface, and the device at the other end is an unbalanced interface. In the case where the requirements are not very strict, only the balanced connection method is used at the balanced end, and the unbalanced connection is used unbalanced. Law, pay attention to the corresponding foot can be. In the case of strict requirements, it is necessary to use a conversion circuit to turn the balance into an imbalance or to turn the imbalance into a balance.
Line code
In a broadcast control room, the number of video and audio cables connected to each signal is quite large. At the same time, because the location is very concentrated, if you do not encode each cable, it will bring extreme maintenance to the future. Great inconvenience. The method is very simple. Before making the connector, you can put the line code on the two ends of the AV cable according to the pre-programmed number. The principle of coding is simple and intuitive. Encoding that is too complicated or too abstract is also not easy to maintain.
It is recommended to use a combination of letters and numbers, such as: VD101 represents the first output (01) of the video (V) splitter (D) No. 1 (1). Through such a set of codes, it is explained that: 1. Signal property: video signal; 2. Signal source: video distributor; 3 device number: No. 1 machine; 4. Port position: No. 1 output port.
The letters can be selected from commonly used English abbreviations, Chinese pinyin or other easy-to-understand letter combinations. The common English abbreviations are listed below for reference.
Abbreviation original meaning
V VIDEO video
A AUDIO audio
B BBLACK BURST black field (synchronous signal)
P PLAYER
R RECORDER deck
D DISTRIBUTER dispenser
M MONITOR monitor
CG CHARACTER GENERATOR captioning machine
O OPTICAL RECEIVER Optical Receiver
T TBC time base corrector
No matter what kind of coding method is adopted, it is planned in advance to form a standard, and at least one coding method is uniformly used in one system. After completing the system, you must keep the line code table in a safe place for future reference.
Audio / video cable Overview <br> video cable, referred to as a video line, and the video cable connector of two parts, wherein: the video cable is a 75-ohm characteristic impedance (ohms) of the coaxial shielded cable, common specifications in a line The diameter is divided into two types, namely -3 and -5. There are two kinds of single-core wire and multi-core wire according to the core wire. The common specifications of the connector are divided into two types: the crimping joint and the welding joint according to the cable end connection mode. The connection method is divided into BNC (commonly known as card head) and RCA (commonly known as lotus head).
The audio cable, referred to as the audio cable, is composed of an audio cable and a connector. The audio cable is generally a double-core shielded cable. The common connector is RCA (commonly known as lotus head), XLR (commonly known as card head), and TRS. JACKS (commonly known as the pen head).
Video cable
The video line is an important part of the video system of the TV broadcast control room. The quality of the production directly affects the technical indicators of the video channel. The poor quality video line may cause the signal to be reversed, the signal is seriously attenuated, the device is not synchronized, and even the signal is interrupted. In addition to a small number of control signal lines in the video system, signals such as program signals, synchronization signals, and key signals are transmitted by video lines , and thus problems in the video lines are one of the common sources of failures in equipment and system failure.
In the process of making a video cable , you must first select the correct video cable and connector. The cable should first be noted for its nominal impedance. A cable with a characteristic impedance of 50 Ω is similar in appearance to the video cable and must not be confused. In addition, attention should be paid to the occurrence of oxidation of the cable or connector. The cable or connector should be scrapped or disposed of as appropriate. Otherwise, the oxide will cause solder joints to be soldered, resulting in severe signal attenuation or even interruption. There are individual manufacturers in the market to cut corners, and the production of video lines does not meet the specifications, such as: sparse shielding, wire diameter is not standard, etc., also pay attention when buying. In the selection of the connector, try to meet the needs of the equipment, avoid using the adapter, and the specifications should be used according to the specifications of the cable.
Secondly, good crimp quality or weld quality must be guaranteed. The use of crimping joints is very strict on the wire diameter and crimping process of the various layers of the cable. It is easier to make on the surface, but if you pay little attention, it may be connected. If you plug it frequently, the reliability will be lower. Should avoid using this type of joints as much as possible. When it is necessary to use it, it is best to press it after welding, and at the same time, avoid using force on the cable when plugging and unplugging. Relatively speaking, the welding type joints have lower requirements on the process, but it is still necessary to pay attention to the specifications of the joints to be consistent with the cable specifications. The welding requirements are the same as those for welding common electronic circuit boards. The solder joints should be smooth and flat without any solder joints. .
Finally, you must check for open or short circuits. Whenever a video cable is made , no matter what the connector or length, it is necessary to check with a multimeter to determine that there is no open circuit or short circuit.
Audio cable
The audio line is more complicated than the video line . In addition to the above three considerations, there is also a problem of balanced and unbalanced connection.
The so-called balanced connection method is a method of connecting a pair of balanced signals by using two signal lines. Since the interference levels of the two signal lines are the same, the phases are opposite, and finally the interference is cancelled. Due to the low frequency range of the audio, it is susceptible to interference under long-distance transmission. Therefore, the balanced connection is an interference-free connection method, which is most common in audio connections of professional equipment. The two-core shielded cable is also used as an audio connection cable in the connection line of the household appliance. However, it transmits the left and right channels, which are two signals and are not balanced.
Unbalanced connection is a connection method that uses only one signal line to transmit signals. Since this connection is susceptible to interference, it is generally used only in household appliances or in some cases where the requirements are low.
The specific connection method is taken as an example of XLR connector: 1. Balance connection: 1 pin connection shield, 2 pin connection + end (also called hot end), 3 pin connection end (also called cold end); 2. Unbalanced connection Method: 1 pin and 3 pin are connected to shield, 2 pin is connected to + end (signal end).
The choice of connection is generally based on the specific requirements of the interface of the device. You can use the balanced connection method as much as possible. When connecting, be sure to read the instructions on the panel first. It is best to read the instructions on the instruction manual and Claim. In some cases, it may be encountered that the device interface at one end is a balanced interface, and the device at the other end is an unbalanced interface. In the case where the requirements are not very strict, only the balanced connection method is used at the balanced end, and the unbalanced connection is used unbalanced. Law, pay attention to the corresponding foot can be. In the case of strict requirements, it is necessary to use a conversion circuit to turn the balance into an imbalance or to turn the imbalance into a balance.
Line code
In a broadcast control room, the number of video and audio cables connected to each signal is quite large. At the same time, because the location is very concentrated, if you do not encode each cable, it will bring extreme maintenance to the future. Great inconvenience. The method is very simple. Before making the connector, you can put the line code on the two ends of the AV cable according to the pre-programmed number. The principle of coding is simple and intuitive. Encoding that is too complicated or too abstract is also not easy to maintain.
It is recommended to use a combination of letters and numbers, such as: VD101 represents the first output (01) of the video (V) splitter (D) No. 1 (1). Through such a set of codes, it is explained that: 1. Signal property: video signal; 2. Signal source: video distributor; 3 device number: No. 1 machine; 4. Port position: No. 1 output port.
The letters can be selected from commonly used English abbreviations, Chinese pinyin or other easy-to-understand letter combinations. The common English abbreviations are listed below for reference.
Abbreviation original meaning
V VIDEO video
A AUDIO audio
B BBLACK BURST black field (synchronous signal)
P PLAYER
R RECORDER deck
D DISTRIBUTER dispenser
M MONITOR monitor
CG CHARACTER GENERATOR captioning machine
O OPTICAL RECEIVER Optical Receiver
T TBC time base corrector
No matter what kind of coding method is adopted, it is planned in advance to form a standard, and at least one coding method is uniformly used in one system. After completing the system, you must keep the line code table in a safe place for future reference.
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