This standard applies to the recording and exchange of two-channel (two-track) stereo broadcast programs on 6.3mm tape. GB/T 5439-1996 Recording and exchange of stereo broadcast programs (tape) GB/T5439-1996 Standard download decompression password: www.bzxz.net

ICS33.160.01
National Standard of the People's Republic of China
GB/T 5439—1996
The recording and exchanging of sound broadcasting programmes on stereophonic magnetic tapePublished on July 9, 1996
State Administration of Technical Supervision
Implemented on December 1, 1996
National Standard of the People's Republic of China
The recording and exchanging of soumd broadcasting programmes on stereophonic magnetic tape onstereophonicmagnetictapeGB/T5439—1996
Replaces GB5439—85
The original standard GB543985 was implemented in June 1986. By 1992, it had reached the five-year review cycle stipulated in the "National Standard Management Measures" of the State Administration of Technical Supervision. According to the relevant documents of the Ministry of Radio, Film and Television, China National Radio is responsible for the review of this national standard. After review, it is considered necessary to modify some items. The main content of the modification is to change the working magnetic level from 255nWb/m to 320nWb/m. The purpose of doing so is: first, to improve the quality of broadcast programs, second, to facilitate international program exchange, and third, considering that the performance of domestic tapes has been greatly improved, it can also promote their stable quality.
After the modification, the following standard is formed through routine procedures to replace GB5439--851. Scope of application
This standard applies to the recording and exchange of dual-channel (two-track) stereo broadcast programs with a bandwidth of 6.3mm magnetic tape. 2 Reference standards
9 Reels and reels of broadcast recording tapes
GB1782--89Www.bzxZ.net
GB4013-83
3 Terminology of audio and video recording
3 This standard adopts the following definitions
3.1 Short-circuit belt flux (referred to as belt flux)
The magnetic flux flowing through the reproducing head core with zero magnetic resistance and in close contact with the surface of the magnetic tape in an infinite length is referred to as belt flux. When the short-circuit belt flux is expressed as a sinusoidal quantity in nanowebers per meter of track width, it generally refers to the effective value. 3.2 Magnetic level
The short-circuit magnetic flux per unit track width is called the magnetic level. The unit is expressed in nWb/m (effective value). 3.3 Operating level operating level
The magnetic level that makes the volume meter indicate the OVU scale. This standard stipulates: When recording with a reference frequency signal, when the tape speed is 38.1cm/s or 19.05cm/s, the magnetic level of 320nWb/m is used as the operating magnetic level.
3.4 ​​Reference frequency reference frequency The specific test frequency when conducting electroacoustic performance tests. This standard stipulates: When the tape speed is 38.1cm/s or 19.05cm/s, 1000Hz is used as the reference frequency. 3.5 Magnetic track
The trace of magnetization of the magnetic head on the magnetic tape is recorded. 3.6 Transmission channel
The path for transmitting electrical signals is called a channel.
Approved by the State Administration of Technical Supervision on July 9, 1996 and implemented on December 1, 1996
GB/T5439—1996
In two-channel stereo, it is divided into left channel and right channel. 4 Technical requirements
4.1 Tape speed
The main tape speed is 38.1cm/s.
The auxiliary tape speed is 19.05cm/s.
4.2 Tape flux frequency characteristics
The time constant of the tape flux frequency characteristic curve is shown in Table 1. Table 1
Tape speed, cm/s
4.3 Shape and position dimensions of recording tracks
Time constant, us
infinity
infinity
4.3.1 The magnetic tape runs from left to right. Looking from the back of the tape, the upper track corresponds to the left channel, and the lower track corresponds to the right channel. There should be a protective barrier between the two tracks.
4.3.2 The shape and position dimensions of the magnetic track are shown in Figure 1 (the shape and position dimensions of Figure 2 are allowed to be used for transition) A
Record trace
Figure 1 Two tracks, one dual channel, one direction, one stereo recording 4.4 Volume meter
Record speed scale
GB/T5439—1996
@0.128 2.3
The VU meter and peak volume meter (PPM) should be used for monitoring the broadcast program on the old tape
Two tracks, two channels, one direction, stereo recording. The performance of the VU meter should comply with the provisions of the guiding technical document "Technical Conditions for Volume Meters" of the Ministry of Radio, Film and Television, and the peak volume meter should refer to the DIN standard. 4.5 Tape reel and rack
The specifications and performance of the tape reel and rack used for recording broadcast programs should comply with the provisions of GB1782. 4.6 Maximum diameter of a full reel of tape
The outer diameter of a full reel of tape shall not exceed 290mm. 4.7 Leader tape and blank tape
4.7.1 When exchanging program tapes, a 1.5m long non-magnetic leader tape should generally be connected at the head and tail of each reel. If a non-magnetic leader tape is not connected, a blank section of not less than 1.5m in length should be left before and after the program section. 4.7.2 For tapes with leader tapes, a blank section of 1s to 2s should be left before and after the start of recording. 4.8 Recording format before and after the program
4.8.1 For tapes for exchanging programs, a calibration signal should generally be recorded after the blank section following the leader tape at the beginning and before the start of the program. The specific items, time and specifications are shown in Figure 3.
Conclusion
Left channel heat signal
Name channel adjustment
Note: Left and right channel level adjustment signals are recorded with reference frequency to the working magnetic level. Blank
4.8.2 When recording a program with a recorded tape, it must be demagnetized first, and the demagnetization must be performed for more than 30 seconds after the recorded program is finished. 4.8.3 When exchanging tapes for programs, if a tape records several independent programs, the interval between programs should be more than 5 seconds. 4.9 Volume requirements for recorded programs
When playing with the working magnetic level, the pointer of the volume meter indicates the 0VU scale as a reference. The maximum volume of the program signal should generally not exceed the ovU scale of the volume meter.
4.10 Requirements for electrical performance of program reproduction channel 4.10.1 Amplitude-frequency response of two channels (left and right channel) The allowable errors of amplitude-frequency response of left and right channels are as follows: 40Hz~125Hz: dB
125Hz~630Hz: ±1dB
630Hz~1250Hz: ±0.5dB
1250Hz~10kHz: ±1dB
10kHz~15kHz: dB
4.10.2 Recording level difference between two channels GB/T5439—1996
In the frequency range of 125Hz~10kHz, a level difference of 1.5dB is allowed. Outside this frequency range, the level difference is allowed to gradually increase to 40Hz and 16kHz, which is 2dB.
4.10.3 Phase difference between two channels
In the frequency range of 250Hz~4000Hz, the maximum phase difference is 15. Outside this frequency range, the phase difference is allowed to gradually increase to: 30% at 40Hz, 65° at 16kHz
4.10.4 Crosstalk between two channels
In the frequency range of 250Hz~4000Hz, the crosstalk does not exceed -35dB. Outside this frequency range, the crosstalk value is allowed to gradually increase to: -20dB at 40Hz; -25dB at 16kHz. 4.10.5 Weighted signal-to-noise ratio 1)
The weighted signal-to-noise ratio of the left and right channels and the sum of the left and right channels is better than 51dB 4.10.6 Total harmonic distortion
The total harmonic distortion of the left and right channels and the sum of the left and right channels should be less than or equal to the following values: 40~125Hz: 2%
125Hz8kHz: 1.6%
5 Marking
5.1 Leader color
5.1.1 Head leader
When the tape speed is 38.1cm·s—green and white stripes, when the tape speed is 19.05cm·s—yellow and white stripes. 5.1.2 Tail leader—red and white stripes. 5.2 Program tape markings
5.2.1 The surface of the program tape box should have the word "stereo" or symbol clearly marked. 5.2.2 For recorded tapes with non-magnetic leader tapes, the program number should be marked on the inside of the leader tape. For recorded tapes without leader tapes, a mark can be added on the core.
5.2.3 Each recorded tape should be accompanied by a program record sheet, which should be attached to the inside of the tape box. The sheet should generally indicate the following items: Name of the recording unit;
Program name,
Author, performer;
Program number:
Number of tape reels used for this program;
1) The signal-to-noise ratio should be measured using a quasi-peak meter with a weighted network according to CCIR468-2 Recommendation. 4
Disc number;
Program time of this disc;
Tape speed,
Recording type (stereo);
Maximum recording level (international exchange program); Noise reduction system,
Protection gap size,
Number of tracks and application method;
Playback time;
Recorder and recording date.
Additional notes:
GB/T5439—1996
This standard was proposed by the Ministry of Radio, Film and Television of the People's Republic of China. The Standardization Planning Institute of the Ministry of Radio, Film and Television of the People's Republic of China is responsible for the technical coordination of this standard. This standard was drafted by China National Radio. The main drafter of this standard is Wen Xiaoke.
This standard was first issued in 1985.
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