JPS5846480Y2 - Recording/playback device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a recording and reproducing device suitable for use in audio information service devices using magnetic disks, and in particular converts audio analog signals into digital signals and converts the digital signals into a storage device at high speed. The present invention relates to a recording and reproducing system in which a signal that has been read out, FM-modulated, and recorded on a magnetic disk is written into a storage circuit through a demodulation circuit, and read out at a low speed to emit an audio analog signal.

Traditionally, magnetic disks have been used as computer terminal storage devices.

It is used for still image recording, etc., but audio information signals are recorded as tracks on magnetic disks, and audio signals for each phrase are extracted from these trunks to provide audio information services,
The present applicant has previously proposed that the present invention can be used for train announcements, forecast announcements on telephone lines, automatic transmission of commercial broadcasts, etc.

However, when recording signals on such a magnetic disk, the response speed is slow and the information cannot be read out from the file at high speed.

In order to eliminate these drawbacks, the present invention reads a time-compressed digital signal at a higher speed than the storage circuit, writes it to a magnetic disk synchronized with the reading speed, and writes it to the playback storage circuit during playback. Digital signals are read out at low speed.

Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3.

FIG. 1 is a diagram for explaining the principle of the present invention. For example, when a magnetic disk is used in a video desk, etc.
Assuming that the rotation speed is 800 r, pm, and the audio signal band is <30 Hz to 5000 Hz as shown in (1) in Figure 1, in order to time-compress the signal, the signal of the magnetic disk is 000 Hz. If the rotational speed of 1800 r, p, m during recording is set to 180,000 or, p, m, which is 1000 times higher during playback, the audio band will be <30 KHz to 5 M, as shown in (2) in Figure 1.
HzK transfer is possible.

However, the rotation speed of the magnetic disk is 1800000r, p,
Since it is difficult to reduce the number of pixels to m, in one embodiment of the present invention, compression is performed electrically and temporally using a memory circuit.

That is, in FIG.
An audio analog signal in a frequency band of about 5 KHz is added, this signal is passed through an amplification circuit 4, sampled and held in a sampling hold circuit 5, and the signal from this is converted into a digital signal in an analog-to-digital conversion circuit 6. This digital signal is stored in the storage circuit γ.

In this case, if the sampling frequency is set to 12 KHz using the clock from the signal generation circuit 8, for example,
Writing to the memory circuit γ is also at 12 KHz.

Next, if reading from the memory circuit 1 is set to 12 MHz, the compression ratio will be increased by 1000 times.

The digital signal read from the storage circuit T is supplied to a digital-to-analog conversion circuit 9, where it is converted into an analog signal, and the analog-converted signal is sent to a high-pass filter circuit 10.
30KHz ~ 5MHz signal is extracted through
This signal is supplied to a frequency modulation circuit 11, frequency modulated, and the modulated high frequency signal is passed through an amplification circuit 12 to a magnetic disk 13 which is rotated by a motor 14 with a rotational speed of 180 Or, p, m. to be recorded.

During playback, the high frequency signal from the magnetic disk 13 and the amplification circuit 15 are supplied to the demodulation circuit 16, and the demodulated high frequency signal is sampled and held in the sample hold circuit 17, and further processed in the next stage analog-to-digital conversion circuit 18. The signal is digitized, supplied to the memory circuit 19, written at high speed using a 12 MHz clock from the signal generating circuit 8, and further read out from the memory circuit 19 using the slow 12 kHz clock from the signal generating circuit 8. This read signal is converted into analog by a digital-to-analog conversion circuit 20, this signal is amplified by an amplification circuit 22 through a low-pass wave circuit 21, and the signal from this is taken out from an output terminal 23 as an analog signal.

In this way, the original signal of 20 Hz to 5 KHz can be reproduced.

Consider a case where information such as a weather forecast is transmitted over the telephone, for example, using a magnetic disk having the above-described configuration.

Normally, people who listen to weather forecasts over the phone pick up the phone receiver at a time lag from the beginning of the weather forecast, so they listen to the forecast from the beginning of the weather forecast information. It is normal that this is not possible.

Therefore, when rotating endless cartridges to flow information, it is possible to shift the heads of multiple cartridges so that the same information source is transmitted, but the response speed is slow, reliability is lacking, and the configuration and operation are complicated. becomes.

On the other hand, according to the magnetic disk having the above configuration, by providing a plurality of storage circuits and digital-to-analog conversion circuits on the playback device side, multi-channel playback becomes possible at the same time.

This will be described in detail with reference to FIG.

In Fig. 3, the same parts as in Fig. 2 are denoted by the same reference numerals, and plural parts are indicated with the suffix a-n''&, and detailed explanation thereof will be omitted. .

Now, if the playback time of one trunk of a magnetic disk is 33 seconds, is the memory circuit better than the analog-to-digital conversion circuit 18? 9a
, 19b, . . . , 19n is written by compressing the time to 33 milliseconds.

Within the track signal time of 33 milliseconds, information from the A phrase 26a to the N phrase 26n is recorded, for example, at intervals of 33 microseconds, as shown in FIG. A channel designation signal 26 is applied so that the phrase 26a of A is extracted and stored in the first storage circuit 19a.

That is, the 5 channel designation signal 26 is transferred to the storage circuit switching circuit 24.
In addition, this output gates the gate circuit 25 inserted between the analog-to-digital conversion circuit 18 and each of the memory circuits 19a to 19n.

In this way, the audio signal in the storage circuit 19a can be converted into a digital signal.
A low frequency audio signal is output to an output terminal 23 through an analog conversion circuit 20a, a low-pass filter circuit 21a, and an amplification circuit 22a.
It can be extracted as the channel 1 signal on a.

Similarly, in the second rotation, B's phrase 26b
is written into the first memory circuit 19a, and the second memory circuit '1
The gate circuit 25 writes the phrase 26a of A to 9b.
By gating the channel 2 signal to output terminal 2
It can be taken out from 3b.

By proceeding with the same operation for N phrases, it is possible to delay the same information 'of channel 1 by one rotation (33 ms) for channel 2, so that cue playback of several channels can be performed simultaneously.

Since the present invention is configured as described above, in various audio services, it is possible to easily perform large time compression, instantaneous cueing, fast response speed, high reliability, etc.
Its practical effects are significant.

The frequency modulation (FM) recording method adopted in this invention is because
This is because this method has the following advantages.

By using a limiter during reproduction, it is possible to correct vibrational fluctuations in the reproduced signal and easily reduce noise.

Note that the digital (PCM) recording method requires a complicated encoder and decoder, which also leads to an increase in price, so this method was not adopted in the present invention.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the principle of the present invention, Fig. 2 is a system diagram of the present invention, Fig. 3 is a system diagram showing a modification of Fig. 2, and Fig. 4 is a system diagram of the third embodiment.
It is a track signal explanatory diagram for explaining a figure. In the figure, 3 is the input terminal, 4, 15.22 is the amplifier circuit,
5.11 is a sample hold circuit, 6°18 is an analog-to-digital conversion circuit, γ, 19 is a storage circuit, 9.20 is a digital-to-analog conversion circuit, 10.21 is a filter circuit,
11 is a modulation circuit, and 16 is a demodulation circuit.

Claims (1)

[Scope of utility model registration request] Analog-to-digital conversion of the audio signal is performed, the digitally converted signal is written to a recording memory circuit at low speed, and the digital signal continued at high speed from the recording memory circuit is converted to analog to produce a frequency-modulated high-frequency signal. 1) Recording on a disk in synchronization with the readout speed of the recording memory circuit, demodulating the reproduced signal from the disk and converting it from analog to digital;
A recording/reproducing device which writes the digitally converted signal into a reproduction memory circuit at high speed, digital-to-analog converts the digital signal read out from the reproduction memory circuit at low speed, and reproduces the original audio signal. At the same time, the high frequency signals of A, B, . . . , N phrases (N22) are sequentially recorded on the disk, and the reproduction storage circuit is connected to a + b + . . . , n. and N pieces (n = N)
A gate circuit writes the signal of the A phrase to the reproduction memory circuit a during the first rotation of the disk, and writes the signal of the A phrase to the reproduction memory circuit a during the second rotation. At the same time as writing to the circuit bK, the signal of the B phrase is written to the reproduction memory circuit a, and thereafter this is sequentially repeated, and each of the reproduction memory circuits albl.
. . . A recording/reproducing device configured to reproduce original audio signals consisting of N phrases of A, B, .