JPS60187974A - Time code signal recording system - Google Patents

Abstract

PURPOSE:To equalize electromagnetic conversion characteristics of recording and reproducing to simplify the circuit constitution by unifying recording periods of one frame in different speeds to the recording period of a prescribed number of bits in one speed. CONSTITUTION:With respect to a time code signal generator 15, when the frequency of clocks supplied to a shift register 17 is 4.41kHz, a time information signal from a generator 16 is loaded to the register 17 by a load signal, which is generated at intervals of 1/30 seconds, and is shifted by said clocks and is outputted as a series signal. When the frequency of clocks supplied to the register 17 is 4.80kHz, the time information signal from the generator 16 is loaded to the register by the load signal, which is generated at intervals of 1/30 seconds, and is shifted by said clocks and is outputted as a series signal. As the result, lengths of two time code signals TCS1 and TCS2 on a magnetic tape TP are equal to each other, and electromagnetic conversion characteristics of recording and reproducing are equalized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an imcode signal recording system suitable for application to a digital audio tape recorder.

Background Art and Problems There are various conventional digital audio tape recorder systems, one example of which will be explained below. That is, there is a method of recording a digital audio signal on a cassette tape using a 22-channel fixed magnetic head and reproducing it. In this method, the following three standards rooms are proposed.

(First standards room) Number of audio channels: 20 x 2 Number of Teisuke channels: 2 x 2 Sampling frequency: 44.1 kHz Number of quantization: 16 bits/sample Tape running speed: 4.76 cm/sec Transmission rate: 2.
352 Mbit/se+: Transmission rate of the second auxiliary channel when running at constant speed 4.41 kbit/5ec (second draft standard) Number of audio channels 20×2 Number of auxiliary channels 2×2 Sampling frequency 48.0kHz Number of quantization 16 bits/sample Tape running speed 5.18 cm/see Transmission rate 2.560 M bits/sec Recording density 62.8 bits/2.54 cm Transmission rate when running at constant speed of the second auxiliary channel 4.80 k bits/see 5ec (Third standard draft) Number of audio channels: 20×2 Number of auxiliary channels: 2×2 Sampling frequency: 32.0k) lz quantization number: 12
Bit/sample tape running speed 2.60cm/5ec5.18c
m/sec Transmission rate 1.280 Mbit/sec Recording density 6
2.8 Hint/2.54 cm Second auxiliary channel at constant speed transmission rate 2.40 Hit/sec In such a digital audio tape recorder, each half of the width of the tape has 20 audio channels and the first and a second auxiliary channel, digital audio signals are recorded in the 20 audio channels, still image signals are recorded in the first auxiliary channel, and time code signals are recorded in the second auxiliary channel. recorded.

OBJECTS OF THE INVENTION The present invention provides a method for moving a tape at first and second speeds Sa, 5b (S
In the time code signal recording method in which the time code signal is recorded on a time code signal recording track separate from the information signal recording track by running at This paper attempts to propose a method that can simplify the circuit configuration.

SUMMARY OF THE INVENTION The present invention provides a method for moving a tape at first and second speeds Sa, 5b (S
a > Sb), and the time code signal is recorded on a time code signal recording track separate from the information signal recording trunk, in which the first and second speeds Sa, When the ratio of Sb is expressed as a ratio of mutually prime integers A and B, the number of bits in one frame at the first and second speeds Sa and Sb of the time code signal is kA, respectively.

kB (however, k = L2.3...), and α bits (however, α-L2,3...) are selected in one frame of the time code signal at the first speed Sa. By adding dummy bits, the recording time of one frame at the first and second speeds Sa and Sb is set to k at the second speed sb.
This is characterized by unifying the recording time of B hints.

According to the present invention, the tape is moved at the first and second speeds S.
a, Sb (Sa>Sb), and the time code signal is recorded on a time code signal recording track separate from the information signal recording trunk. It is possible to obtain a device that has the same conversion characteristics and can simplify the circuit configuration.

EXAMPLE Below, an example of the present invention will be described with reference to FIG. (LL) and (IR) are input terminals for left and right analog audio signals, and these left and right analog audio signals are each passed through a low-pass filter (2L).

(2R) through sampling halt circuit (3L)
.

(3R) and then to an A/D converter (4) where it is digitized. The output of the D/D converter (4) is supplied to the P(J+ encoder (5)). The 20-channel digital audio signal obtained by signal processing such as interleaving by the PCM encoder (5) is 8-10 conversion encoder (6) and amplifier (
7) to each magnetic head (8) and recorded on the magnetic tape TP.

(9) is a system controller which controls the sampling and holding circuits (3L), (3R), A'/D converter (4) and P encoder (5). The pot is a changeover switch and has a grounded movable contact m and fixed contacts a and b connected to a system controller (9). Here, according to the first and second standard chambers described above, the changeover switch or movable contact m is connected to fixed contacts a and b.
can be switched to

(10) is an input terminal to which a digital signal such as a still image signal is supplied, and this signal is supplied to a sub-encoder (11). The digital signal from this sub-encoder (11) is supplied to an 8-10 conversion encoder (12), and then
The signal is supplied to the magnetic node (20) through the amplifier (13) and recorded on the magnetic tape TP. It is configured. In this example, the shift register (17) is set to have 147 stages, corresponding to the above-mentioned first standard chamber. This shift register (1
7) is supplied with a clock signal of Zamplinter frequency/10 and a load signal with a period of 1/30 seconds, for example, from the system controller (9). Also, a ground potential is supplied to its series input terminal. Then, the time information signal from the time information signal generator (16) is transmitted to the shift register (1
7) Served in 44 rows. The serial digital output of the shift register (17) is connected to the FM modulator (18) and the amplifier (1).
9) to the magnetic head (20) and recorded on the magnetic tape TP.

FIG. 2 shows a half-width track pattern of the magnetic tape TP, including audio trunks T(1) to T(20) and first and second auxiliary trunks T(Xi).

T (X2) is provided. The same holds true for the other half of the track pattern of the width of the magnetic tape TP.

I5 is the center line of the tape TP.

Figure 3 shows audio tracks T(1) to T(20)
It shows the block pattern of the digital audio signal to be recorded on the 8-bit professional synchronization signal bit SY, 8
A block address signal bit RΔ of 4 bits, a discrimination signal bit D of 4 bits, a CRC code signal bit of 12 bits CRC, and a data signal word C(0), C(1) to C( 27).

FIG. 4 shows a frame pattern of a time coat signal (SMPTE format is available) recorded on the second auxiliary track T (X2). In Fig. 4, Te3 (1
) and Te3 (2) indicate each frame of the first and second Quimco-1 and " signals corresponding to the above-mentioned first and second draft standards, respectively. Frame TC of the first time code signal
5(1) is, for example, a 16-bit frame synchronization signal bit SY, a 28-bit relative time (hour, minute, second, frame number) signal via) RTC 128-bit absolute time (
Hours, minutes, seconds, frame number) BTC159 to signal hit
It consists of a control signal bit CTL of 1 bit and a CRC coat signal bit CRC of 16 bits, for a total of 147 hints.

Frame TC5(2) of the second time code signal is also mostly the same as frame TC5(1) of the first time code signal, but the difference is that the CRC code signal H is CRC followed by 13 Hiso I- The point is that a dummy hiso) DB is provided.

and frame T of the first and second time code signals.
The recording time of C5 (1) and Te3 (2) is equal to 1/3
It is 0 seconds.

In this example, Sa, Sb, A
, B, k and α are as follows, respectively.

5a=5.18cm/sec,,Sb=4.76c
m/5eck-1, α-13 Next, the time coat signal generator (15) of the circuit in Figure 1
Explain the operation. When generating the first time code signal, the frequency of the clock signal supplied to the shift register (17) is 4.41 kHz, and the time information signal from the time information signal generator (16) is transmitted every 1/30 seconds. After being loaded into the shift register (17) by the load signal of , it is shifted by this clock signal and is available at its output terminal as a serial digital output.

When generating the second time code signal, the frequency of the clock signal supplied to the shift register (17) is 4.
At 80kllz, the time information signal from the time information signal generator (16) is loaded into the shift register (17) by the load signal every 1/30 seconds, then shifted by this clock signal and its output as a serial digital output. obtained at the output terminal. However, the dummy pin (DB) is created by shifting the ground potential from the serial input terminal by a clock pulse.

In this way, the frame TC3(1) of the first and second time code signals corresponding to the first and second draft standards described above.
, Te3 (2) have the same length on the magnetic tape TP, and the electromagnetic conversion characteristics for recording and reproduction are the same, so there is no need to provide a difference in characteristics in the circuit configuration.

A digital audio tape recorder using such a time code signal recording method can reproduce audio information in synchronization with video information by operating in synchronization with a VTR.

Note that there may be three or more tape running speeds, in which case a dummy hit (;J In addition, the recording times of one frame may be made the same.

Note that a desired data signal can also be input into this dummy bit.

Furthermore, in the case of the third draft standard, the time code signal according to the second draft standard may be used once every two frames.

Note that the present invention can also be applied to tape recorders that record video signals.

Effects of the Invention According to the present invention described above, the tape is run at the first and second speeds Sa and Sb (Sa>Sb), and is placed in a time code signal recording trunk that is separate from the information signal recording trunk. In a time code signal recording method for recording a time code signal, it is possible to obtain a system in which the electromagnetic conversion characteristics for recording and reproduction can be made the same and the circuit configuration can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a digital audio chip recorder to which the present invention is applied, FIG. 2 is a pattern diagram showing a tape trunk pattern, and FIGS. 3 and 4 are diagrams showing signal formats. be. TP is a magnetic tape, T (X2) is a time code signal recording track, and Te3 (1) and Te3 (2) are frames of the first and second time code signals.

Claims (1)

[Claims] The tape is moved at first and second speeds Sa, Sb (Sa>Sb
), and the time code signal is recorded on a time code signal recording trunk separate from the information signal recording track.
When the ratio of the first and second speeds Sa and Sb is expressed as a ratio of mutually prime integers A and B, bits of one frame at the first and second speeds Sa and Sb of the time code signal kA each. kR (however, k = 1.2, 3, . . . ) is selected, and α bits (however, α = 1.2, 3, . . . ) are selected in one frame of the time code signal at the first speed Sa. ) are added to obtain the first and second speeds Sa. A time code signal recording method characterized in that the recording time of one frame at the second speed sb is unified to the recording time of kB bits at the second speed sb.