This standard specifies the dimensions and mechanical properties required for the interchangeability of audio cassette tapes, and specifies the corresponding measurement methods. This standard applies to audio cassette tapes with a bandwidth of 3.81 mm, but does not include microcassette tapes. GB/T 3791-1999 Dimensions and Mechanical Properties of Audio Cassette Tapes GB/T3791-1999 Standard Download Decompression Password: www.bzxz.net

ICS33.160.30
National Standard of the People's Republic of China
GB/T3791-1999
Cassette for tape per recorders
dimensions and mechanical characteristics1999-08-02 Issued
Implementation on 2000-03-01
Issued by the State Administration of Quality and Technical Supervision
GB/T3791—1999
This standard is a revision of the national standard GB3791-1983 "Dimensions and mechanical characteristics of cassette tapes". The main parameters in this standard are equivalent to the corresponding parts of the international standard IEC94-7:1996 "Commercial audio and household cassette tapes". Compared with GB3791-1983, this standard has been modified as follows: a) In Chapter 1, it is clarified that this standard does not apply to microcassette recording tapes. In addition, two chapters, "reference standards" and "definitions", have been added.
b) The contents of the original standard, such as the tape winding torque and the technical requirements for measuring the tape recorder, have been appropriately modified according to the current technical level, and the index requirements have been improved.
The requirements for the length of the leader tape have been added, and the content that the measurement accuracy of the tape cassette integrated gauge is 0.01mm has been removed. c) Taking into account the current domestic actual situation and technological development, the standard retains the original measurement method, and at the same time clarifies that other measurement methods and measuring equipment that can obtain the same results can be used. The various contents of "measurement method" have been appropriately supplemented and modified according to the actual measurement points and steps to make it clearer and more complete. d) The name of Figure 6 has been changed to "limit dimensions that must be guaranteed for the tape cassette to cooperate with the entire tape recorder", which makes the meaning of the figure clearer and easier to understand.
This standard replaces GB/T3791-1983 from the date of implementation. This standard is proposed by the Ministry of Information Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Recording Equipment. The drafting units of this standard are Shanghai Guangdian Shanglu Electric Co., Ltd. and China Electronics Technology Standardization Institute. The main drafters of this standard are Shen Yunli, Li Xujin, Gan Weiping and Fu Jing. I
1 Scope
National Standard of the People's Republic of China
Dimensions and mechanical characteristics of cassette tape records
Cassette for tape records
dimensions andmechanical characteristicsGB/T3791-1999
Replaces GB/T3791-1983
This standard specifies the dimensions and mechanical characteristics required for the interchangeability of cassette tapes and specifies the corresponding measurement methods. This standard applies to cassette tapes with a bandwidth of 3.81 mm, but does not include microcassette tapes. 2 Referenced standards
The clauses contained in the following standards constitute the clauses of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T2018—1987 Measurement methods for tape recorders (neqIEC94-3) GB/T2019-1987
GB/T4013—1995
3 Definitions
Basic parameters and technical requirements for tape recorders Audio and video recording terms (eqvISO2211:1977) The terms used in this standard conform to the provisions of GB/T4013. 4 Dimensions and mechanical properties
4.1 Tape dimensions
Band width: 3.81-0.05mm;
Maximum thickness: 0.020mm.
4.2 Track position and size
According to the provisions of GB/T2019.
4.3 Cassette size
According to the provisions of Figures 1 to 11.
4.4 Master shaft
The maximum diameter of the master shaft is 3mm.
4.5 Cassette tape support plane
When using the cassette tape, only the support part shown in Figure 7 is allowed to be supported on the tape recorder. 4.6 Winding torque
The torque required for the tape to run in the cassette should be less than 0.2N·cm. 4.7 Pressure pad
When the recording and playback head is extended into the cassette according to the dimensions specified in Figure 9, the pressure of the pressure pad on the working surface of the head should be 0.1N~0.25N. 4.8 Leader tape
4.8.1 Leader tape length
Approved by the State Administration of Quality and Technical Supervision on August 2, 1999, and implemented on March 1, 2000
GB/T3791-1999
The strength of the leader tape should be sufficient to protect the magnetic tape. 4.8.2 Leader tape fixing strengthWww.bzxZ.net
The minimum tensile force that the leader tape and the core can withstand is 10N. 4.9 Bonding strength between magnetic tape and leader tape
The magnetic tape and leader tape after bonding should be able to withstand a tensile force of 3N without breaking or debonding. 4.10 Bonding strength of cassette window
The cassette window should be able to withstand a pressure of 10N without damage. 4.11 Strength of fire-proof sheet
The fire-proof sheet should be able to withstand a pressure of 3N without damage. 4.12 Jitter rate
The jitter rate of recording and playback of cassette tapes shall not be less than ±0.4% (weighted peak value). 5 Measurement method
5.1 Measurement conditions
Temperature: 15℃～35℃, (in case of dispute, the arbitration temperature is 15℃～25℃); relative humidity: 45%~80%;
Atmospheric pressure: 86kPa~106kPa;
Power supply voltage: 220V±3%;
Frequency: 50Hz±0.5Hz.
5.2 Technical requirements for measuring equipment
5.2.1 Recorder for measurement
Tape speed: 4.76cm/s;
Tape speed error: ±0.5%;
Wow and wow rate: ±0.15% (weighted peak); Recording and playback signal-to-noise ratio: better than 48dB (unweighted); Recording and playback amplitude-frequency response: 20Hz～12.5kHz, ±2dB. 5.2.2 Tape box comprehensive gauge
Should meet the measurement requirements of the dimensions in Figures 1 to 11. 5.2.3 Tape winding torque measuring instrument
Turntable speed: 40r/min~50r/min for the head of the tape, 15r/min~20r/min for the tail of the tape; Speed ​​fluctuation: ≤1%;
Torque meter range: 0.9N·cm;
Torque meter accuracy: 0.01N·cm.
5.2.4Special gram meter
Range: 0.5N;
Accuracy: 0.01N.
5.2.5Force gauge
Range: 5N, 20N;
Accuracy: Class II, tolerance ±0.5% (maximum range). 5.2.6Pressure gauge
Range: 5N, 20N.
Accuracy: Class II, tolerance ±0.5% (maximum range). 5.2.7 Wobble meter
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Frequency range: 0.2Hz~200Hz;
Measurement frequency: 3150Hz;
Indication method: weighted peak value;
Weighting characteristics: According to the provisions of GB/T2018. 5.3 Measurement method
GB/T3791-1999
This standard recommends the following measurement methods, but does not exclude other methods that can obtain the same measurement results. 5.3.1 Measurement of tape box size
Measure with tape box integrated gauge (Figure 12) and other conventional measuring tools . Before measuring according to Figure 12, the three reference surfaces X, Y, and Z of the tape cassette should be adjusted to be consistent with the corresponding reference surfaces of the integrated gauge. 5.3.2 Measurement of tape winding torque
Place the cassette tape to be measured on the turntable of the tape winding torque measuring instrument (Figure 13), rotate the turntable at the specified speed, and measure the tape winding torque of the tape head and tail.
5.3.3 Measurement of pressure pad pressure
Press the sensor head of the special gram meter (Figure 14) into the tape cassette at 3.6mm and read the pressure value. 5.3.4 Measurement of the fixing strength of the leader
As shown in Figure 15, fix the core on the shaft, fix the other end of the leader on the dynamometer, gradually increase the tension to 10N, and check whether the leader is detached from the core.
5.3.5 Measurement of the adhesive strength between the tape and the leader tape Fix the bonded tape and the leader tape as shown in Figure 16, gradually increase the tension to 3N, and check whether there is any breakage or debonding.
6 Measurement of the adhesive strength of the cassette window
As shown in Figure 17, fix the cassette, use a pressure gauge to press the middle of the cassette window, and gradually increase the pressure to 10N, and check whether there is any damage.
5.3.7 Measurement of the strength of the fire-proof sheet
As shown in Figure 18, fix the cassette, move the pressure gauge, and gradually increase the pressure on the middle of the fire-proof sheet to 3N, and check whether there is any breakage.
5.3.8 Test of the wow and flutter rate
Connect the 3150Hz oscillation output on the wow and flutter meter to the input end of the measuring recorder, record with the measured tape for several minutes, then replay the tape three times, connect its output to the wow and flutter meter, and take the average of the three readings. 3
Guide surface
GB/T3791—1999
19.2±0.2
37.4±0.2
66.6±0.2
1The radius of each guide surface should be between 0.4mm and 1mm. 2-5.2
Guide surface
2The tape contacts the cassette only at the tape guide surface, at the guide surfaces P and S at both ends. The gap cannot be too large to prevent dust from entering the cassette. All guide surfaces must be perpendicular to the Z reference plane.
Figure 2 Position of the guide surface
Limit of the tape path
Figure 3 Tape path
Maximum free space for the head and the stop sensor to extend into the cassetteFigure 4
GB/T3791—1999
Partial enlargement
Note: The shaded part must be ensured not to contact the tape. Figure 5 Part not in contact with the tape
Reference hole
Note: This figure is a supplement to the standard. The standard dimensions it gives can be used to check whether the position of the plug-in components such as the head and the stop sensor is correct. The standard dimensions of each opening are slightly smaller than the dimensions specified in Figures 1 and 4. This is to take into account the special use requirements of some recording seats. This recording seat has a positioning pin at the reference hole. When in use, its center line may deviate from the Y reference plane: ±0.15mm2=±0.075mm (as shown in the D-D part in Figure 1). This offset is included in the limit size. Figure 6 The maximum dimensions that must be guaranteed for the cassette to fit together with the entire tape recorder 5
Marking part
GB/T3791-1999
Figure 7 Position of the marking and supporting part
Supporting part
.3-0.3
1) The maximum height that the cassette window part is allowed to protrude. 3.5±8:
3.35±8:1
GB/T3791-1999
Figure 8 Cassette window part
Recording head
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Muffler head
Auto stop sensor
Press roller
Figure 9 Specified depth of insert
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GB/T3791-1999
Relationship between the position of the magnetic track of the cassette surface mark and the anti-extinguishing sheet PAdditional sensing hole
66.25±0.25
Additional sensing hole position for high coercivity magnetic tape?
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