JPH0572641B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is applicable to audio signals such as voices and music.
This invention relates to a PCM signal recording device that records PCM signals in parallel as multiple tracks.

BACKGROUND TECHNOLOGY AND PROBLEMS First, a recording magnetic head device in which a plurality of magnetic heads were arranged and fixed in parallel in the vertical direction was used to record PCM signals such as audio and music in parallel as multiple tracks. A PCM signal recording and reproducing device for reproducing the PCM signal has been proposed. In such a PCM signal recording and reproducing device, the high quality of audio, music, etc. is considered, so the number of quantizations is relatively large, for example 16, so that 16-bit PCM signals can be recorded in parallel. The system used a recording magnetic head device in which 16 magnetic heads were arranged and fixed in parallel in the vertical direction, and was configured to record 16 tracks in parallel on a magnetic tape and reproduce them.

In such a PCM signal recording and reproducing apparatus, it is not necessary to set the number of quantizations to 16, for example, for audio, music, etc. that do not particularly require high quality.

Purpose of the Invention In view of the above, the present invention provides a PCM signal recording device capable of obtaining high-quality audio, music, etc. as described above, which is capable of PCM recording audio, music, etc. that do not require high quality. The purpose is to be able to record for longer periods of time.

Summary of the Invention The present invention provides a first PCM signal recording device for recording PCM signals on a plurality of tracks on a magnetic tape using a plurality of magnetic heads arranged and fixed in parallel in a direction perpendicular to the running direction of the tape. means for distributing a quantized number of PCM signals corresponding to the plurality of magnetic heads; and means for distributing PCM signals of a second quantized number smaller than the first quantized number to the plurality of magnetic heads. recording on a magnetic tape, comprising: a means for distributing the data and lengthening the interval between outputs; and a magnetic tape speed control means for changing the magnetic tape feeding speed according to the first or second number of quantizations. It is designed to change the time.

Embodiment An embodiment of the PCM signal recording apparatus of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 indicates an audio signal source such as a microphone, radio receiver, record player, tape recorder, etc.
16-bit linear A-D converter that converts the audio signal into a 16-bit PCM signal with a quantization number of 16.
The signal is supplied to a PCM encoder 2, and also to an 8-bit differential PCM encoder 3 which converts the audio signal from the audio signal source 1 into an 8-bit PCM signal with a quantization number of 8.

In this case, the 16-bit linear PCM encoder 2 obtains a high quality audio PCM signal. For example, when the clock frequency f _S is 44.1 KHz in 16-bit linear PCM conversion, the frequency characteristic of the audio signal is 98 dB in the frequency range of 20 Hz to 20 KHz, and high quality audio can be obtained. this
The 16 output terminals of the 16-bit linear PCM encoder 2 from which 16-bit parallel PCM signals are obtained are respectively connected to one fixed contact group 4a of a changeover switch group 4 consisting of 16 changeover switches.

Also, since the 8-bit differential PCM encoder 3 performs differential PCM conversion, the number of quantization is 8.
Even with 8 bits, it is possible to obtain a PCM signal that is a sufficiently practical audio signal. For example, by using 8-bit differential PCM conversion, the clock frequency f _S can be changed to
When set to 44.1KHz, the frequency characteristic of the audio signal is 780dB at the frequency of 20Hz to 20KHz,
It is fully practical. In this 8-bit differential PCM decoder 3, the 8-bit parallel signals on the output side are
A PCM signal is obtained, and this 8-bit parallel PCM signal is sequentially supplied to 16 latch circuits 3a that store 2 clocks at a time. An output signal is output from the output terminal of the latch circuit 3a, and each of the 16 output terminals of the latch circuit 3a is connected to
are connected to the other fixed contact group 4b of each.

The 16 movable contacts 4c of the changeover switch group 4 are connected to 16, for example, thin-film magnetic heads arranged and fixed in parallel in the direction perpendicular to the running direction of the magnetic tape, respectively, via the recording amplifier circuit 5, as shown in FIG. Magnetic heads 6a, 6b of the recording magnetic head device 6 as shown...
Connect to 6p respectively. In FIG. 2, 12 is an erase head, 12a is a control signal erase head,
Reference numeral 13 indicates a reproducing magnetic head device, and this reproducing magnetic head device 13 includes 16 reproducing magnetic heads 1.
3a, 13b...13p are arranged and fixed in parallel in a direction perpendicular to the running direction of the magnetic tape 11, and the tracks recorded by the recording magnetic heads 9a, 9b...9p are recorded by the respective magnetic heads 13a, 13b...13p. It is designed to be regenerated. 13q is a control track reproduction head.

Further, in this example, the signal obtained at the output side of the 8-bit differential PCM encoder 3 is supplied to the discrimination signal generation circuit 7, and the discrimination signal obtained at the output side of the discrimination signal generation circuit 7 is manually controlled. A control signal is supplied to a tape speed control circuit 9 and a recording head 10 as shown in FIG. 2 through a connection switch 8. In this case, the connection switch 8 is interlocked with the movable contact 4c of the changeover switch group 4, and this movable contact 4c is connected to the other fixed contact 4b.
When the connection switch 8 is connected to
is connected to one of the fixed contacts 4a, the connection switch 8 is turned off.

In this case, the tape speed control circuit 9 controls the magnetic tape 11 when the maximum quantization number of the magnetic tape 11 is 16, for example, and when the currently selected quantization number _N1 is 8, for example, the magnetic tape 11 at the maximum quantization. When the speed of N ₁ /N ₀ is set to 1, for example, the speed is set to 8/16=1/2. In this example, when the tape speed control circuit 9 is supplied with the discrimination signal from the discrimination signal generation circuit 7, the speed of the magnetic tape 11 is set to 1/2. Other configurations are the same as before.

In FIG. 1, when recording a PCM signal to obtain high-quality audio, music, etc., each movable contact 4c of the changeover switch group 4 is connected to one of the fixed contacts 4a, and the connection switch 8 is connected. is off. At this time, the 16-bit PCM signals obtained at the output side of the 16-bit linear PCM encoder 2 are sent to the magnetic head 6 via the recording amplifier circuit 5.
a, 6b...supplied to 6p, as shown in Figure 3.
The 16 tracks 11a, 11b, .

Next, when recording audio, music, etc. of meetings, lectures, etc. that do not require high quality, select switch group 4.
Each movable contact 4c is connected to the other fixed contact 4b.
and turn on the connection switch 8.
At this time, the audio signal from the audio signal source 1 is subjected to 8-bit differential PCM conversion by the 8-bit differential PCM encoder 3, and every time this 8-bit PCM signal is supplied to 16 latch circuits 3a for 2 clocks, the 16 The output terminals of the latch circuits 3a are connected to the magnetic heads 6a and 6 via the recording amplifier circuit 5, respectively.
b...6p, and 16 tracks 11a, 11b...1 are supplied to the magnetic tape 11 as shown in FIG.
Recorded as 1p. In this case, the discrimination signal from the discrimination signal generation circuit 7 is supplied to the tape speed control circuit 9, and the running speed of the magnetic tape 11 is adjusted to 8/8 in the normal state.
16=1/2 and this discrimination signal is recorded on the control track 11q of the magnetic tape 11.
At this time, the running speed of the magnetic tape 11 is reduced to 1/2, but the output signal from the latch circuit 3a is output every two clocks, so the recording density of the PCM signal on this magnetic tape 11 is the above-mentioned 16 This is the same as when the output signal of the bitlinear PCM encoder 2 was recorded. Therefore, at this time, the magnetic tape 11
When the above PCM signal has the same recording density and the same length of magnetic tape 11, the recording time can be doubled.

When reproducing the magnetic tape 11 recorded by the PCM signal recording apparatus as shown in FIG. 1, a PCM signal reproducing apparatus as shown in FIG. 4 is used.
To explain this FIG. 4, in this FIG. 4, parts corresponding to FIGS. 1 and 2 are given the same reference numerals, and detailed explanation thereof will be omitted.

In Fig. 4, it was recorded on magnetic tape 11.
The 16 tracks 11a, 11b...11p are transferred to the 16-bit PCM signals reproduced by the 16 reproduction magnetic heads 13a, 13b...13p via the reproduction amplifier circuit 14, each of which is switched by 16 changeover switches. One of the fixed contacts 15b of each switch group 15 is connected in parallel to the 16 input terminals of the 16-bit PCM decoder 16, and The other fixed contacts 15c are connected in parallel to respective input terminals of 16 latch circuits 17a provided before the 8-bit differential PCM decoder 17. The 16-bit PCM decoder 16 decodes in synchronization with the 44.1KHz clock,
The audio signal obtained on this output side is supplied to one fixed contact 18a of the changeover switch 18.
Furthermore, the 16-bit signals supplied to the 16 latch circuits 17a are supplied 8 bits at a time to the 8-bit differential PCM decoder 17 in synchronization with the 44.1 KHz clock.
The audio signal decoded by the 8-bit differential PCM decoder 17 is supplied to the other fixed contact 18b of the changeover switch 18. This changeover switch 1
The audio signal obtained at the movable contact 18c of 8 is supplied to the speaker 20 via the audio output circuit 19 and reproduced. Further, the signal obtained by the control track reproducing head 13q is supplied to the discrimination signal reproducing circuit 21. When no discrimination signal is obtained on the output side of the discrimination signal reproducing circuit 21, each movable contact 15a of the changeover switch group 15 is connected to one fixed contact 15b, and the changeover switch 1
The eight movable contacts 18c are connected to one fixed contact 18a, the magnetic tape 11 is kept at a steady speed, and high-quality reproduced audio, music, etc. can be obtained.

Further, when a discrimination signal is obtained on the output side of the discrimination signal reproduction circuit 21, the tape speed control circuit 9a is controlled so that the speed of the magnetic tape 11 is reduced to 1/2 of the steady speed.
At the same time, each movable contact 15a of the changeover switch group 15 is connected to the other fixed contact 15c, and the movable contact 18c of the changeover switch 18 is connected to the other fixed contact 18b.
The audio signal decoded by the PCM decoder 17 is reproduced by the speaker 20. Therefore, this fourth
In the figure, a predetermined recorded audio signal can be automatically reproduced under control according to a signal recorded by a PCM signal recording device.

In the above embodiment, an example was described in which the number of quantizations is 16 and 8, but it may be 10, 12, etc. instead of 8, or the maximum number of quantizations may be other than 8. Of course, it is good to do so. Furthermore, the present invention is not limited to the above-described embodiments, and it goes without saying that various other configurations may be adopted without departing from the gist of the present invention.

Effects of the Invention According to the present invention, in a PCM signal recording device that can obtain high quality audio, music, etc.,
When recording PCM audio, music, etc. that do not require high quality, it is possible to record for a longer time and make effective use of magnetic tape.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the PCM signal recording device of the present invention, FIGS. 2 and 3 are diagrams for explaining the present invention, and FIG. 4 is a configuration diagram showing an example of the PCM signal reproducing device. It is a diagram. 1 is audio signal source, 2 is 16-bit linear
PCM encoder, 3 is an 8-bit differential PCM encoder, 4 is a switch group, 5 is a recording amplifier circuit,
6 is a recording magnetic head device, 7 is a discrimination signal generation circuit, 9 is a tape speed control circuit, 10 is a control signal recording head, and 11 is a magnetic tape.

Claims (1)

[Claims] 1. PCM signals to multiple tracks on a magnetic tape,
Recording is performed using multiple magnetic heads arranged and fixed in parallel in a direction perpendicular to the running direction of the tape.
In a PCM signal recording device, means for distributing a PCM signal having a first number of quantizations to the plurality of magnetic heads, and a PCM signal having a second number of quantizations smaller than the first number of quantizations. means for distributing the magnetic tape to the plurality of magnetic heads and lengthening the output interval, and magnetic tape speed control means for changing the magnetic tape feeding speed according to the first or second number of quantizations. A PCM signal recording device characterized in that the recording time on a magnetic tape is changed.