JPS5873008A - signal regenerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a signal reproducing apparatus for reproducing a so-called POM disk or POM tape, in which music sources and the like are recorded in a plurality of four or more channels, in two channels or monaurally.

Hereinafter, a signal reproducing device that reproduces a recorded signal of a 9 POM disk recorded in 4 channels in 2 channels will be explained as an example.

FIG. 1 is a block diagram showing an example of a conventional signal reproducing apparatus that obtains the sum of the front and rear sides of a POM disc recorded in four channels and reproduces it in two channels. In the same figure, a 2Fi digital-to-analog conversion circuit, 21atj input terminals, 3 to 6 resample the signals corresponding to each channel, and Hall r sample and hold circuits, and 7 to 10 a predistributed sample and hold circuit 3. -6 are provided correspondingly to low-pass filters, 11 and 12 are mixers, 13 is a left channel output terminal, 14 is a right channel output terminal, and 20 is a control signal generator.

In addition, Fig. 2 (a) Fi is the output of the digital-to-analog converter circuit 2 shown in Fig. 1. This is a 4-char signal train that is divided and repeated in the order of the channels. However, to represent repetition of the same channel, for example, Lf.

1, 2, etc. on the channel signal, like...
The subscript ``...'' is added.

Also, (1) to Ce> in the same figure are timing charts of control signals (resampling signals) generated by the control signal generator 20 shown in Figure i41.

Of these, (b) Fi is input to the resample hold circuit 3 shown in Figure 1 and is for resampling only the Lr channel, and (C) is the resample hold circuit 5 shown in @1. (a) is input to the resample hold circuit 4 shown in FIG. 1, and is for resampling only the Rf channel. can be,
(e) is input to the resample and hold circuit 6 shown in FIG. 1, and is for resampling only the Rr channel.

Note that the resampling signals (b) to <e) are in a resampling state when they are at a high level 111, and are in a holding state when they are at a low repeat A "0".

The operation of the two circuits of the signal reproducing device shown in FIG. 1 will be explained below.

Four channels of recording signals from a POM disk (not shown) are time-divided into four channels using a generally well-known method.
It is input from the input terminal 21L of the digital-to-analog conversion circuit 2 as a channel digital signal. At this time, the output of the conversion circuit 2 is
As shown in Figure (L)C, four channels of signals are time-divided (connected).

By resampling and halling 1 m#i of the signals of each of the connected channels using the resampling signals input from the control signal generator 20 to the resampling and holding circuits 3 to 6, as described above, It is done. Next, the outputs from the spinning sample hole r circuits 3 to 6 are processed continuously (analog) by low pass filters 7 to 10 provided correspondingly.
converted into a signal.

However, the corner frequencies of the low-pass filters 7 to 10 must be input to the pre-distributed sample and hold circuits 3 to 6, respectively, or set to be lower than the sampling frequency H.

Below, with reference to FIG. 3, the output waveforms of the above-described sample and hold circuits and low-pass filters will be explained with reference to the Lf and Lr signal resampling and holding circuits 3 and 4, respectively, and the corresponding configurations. This will be explained by taking as an example the case of Loaf Yasfil Tough and 8.

FIG. 3 is an output waveform diagram showing an example of the output waveforms of the sample and hold circuits 3 and 4 and the low-pass filters 7 and 8.

In the figure, -projection 21 is the Lf channel Hall signal (L, L, . . ., L fn) output from the Rissanzor Hall P circuit 3. This signal is sent to the output end of the low-pass filter 7 as a smoothed analog signal 22.
becomes. In addition, the staircase wave 23 #'i and the Hall P signal (L
rlj, Lrt...-Lrn).

This signal becomes a smoothed analog signal 24 when the low-pass filter 80 outputs the signal.

Analog signal 2 output from the filters 7 and 8
2 and 24, that is, the Lf and Lr channels, are passed through the mixer 11 to form (Lf + Lr
) is obtained at the L channel output terminal 15 as a mixed signal (L channel signal).

Note that the above explanation has been made using the L channel signal as an example, but the R channel signal, that is, (Rf -1-
Of course, even if the mixed signal V of Rr) is difficult, it can be obtained in the same manner.

As is clear from the above, the conventional signal reproducing device requires resonator filter circuits and filter circuits for four channels, as shown in FIG. It also required two mixers. As a result, the signal reproducing device becomes larger and more complex, and it also becomes expensive.

In order to eliminate such drawbacks, a conventional technique that can be considered is to transfer only the Lf and Rf channel signals among the four channel signals of Lf, Lr, Rf, and Rr to the sample bold shown in Fig. 1. Circuits 5 and 5
This is a method of obtaining left and right stereo signals by resampling and holding the signal.

According to this method, among the blocks of the signal reproducing device shown in FIG. It is clear that reproduction can be performed with a configuration of only 14 and the control signal generator 2o.

As a result, compared to conventional signal reproducing devices, it is possible to realize miniaturization and simplification, and it is also possible to reduce costs.

However, this method has the disadvantage that, for example, only the front signal is reproduced and the rear signal is cut.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and to
When playing POM discs or FiP (! The object of the present invention is to provide a signal reproducing device that can realize further miniaturization, simplification, and cost reduction.

In order to achieve the above object, the present invention provides a pre-distributed sample and hold circuit so that the resample and hold circuit can see into the resample and hold circuit a plurality of channels of signals output from the control signal generator or sampled signals to be synthesized. I decided to enter it.

Further, in order to achieve the above object, in the present invention, the corner frequency of the low-pass filter is set to be less than % of the frequency at which the signal of the same channel is resampled by the all-in-sol hold circuit.

Hereinafter, the present invention will be described in the same way as the explanation of the nine prior art described above.
A case will be explained with reference to the drawings, taking as an example a case where a recorded signal of a POM disk recorded in channels is reproduced in two channels.

Figure 4 shows two paM discs recorded in 4 channels.
FIG. 2 is a block diagram showing an embodiment of the signal reproducing device of the present invention in the case of channel reproduction.

In the figure, 15 is a left channel resample hole r circuit, 16 is a right channel resample hole r circuit, 17.
18 is a low-pass filter, and 30 is a control signal generator. Note that the same parts and equivalent parts as in FIG. 1 are indicated by the same reference numerals.

5(-) is the output of the digital-to-analog converter 2 shown in FIG. 4, similar to FIG. 2(a), and Lf,
This is a four-channel signal train that is time-divided into Rf, Lr, and Rr and repeated in the order of the channels. However, in order to represent repetition of the same channel, subscripts 1, 2, . . . are added to the channel symbols, similar to (-) in FIG.

(g) and (h) of the same figure are timing charts of the control signal (resampling signal) generated by the control signal generator 30 shown in FIG. 14.

Of these, (g) is equal to the logical sum of the sampling signal (b) and ((1) in FIG. .Also, (h) is the second
It is equal to the logical sum of the sampling signals (e) and (6) in the figure, and is input to the right channel resample and hold circuit 16, and is used to resample the RE and Rr channels.

In addition, the predistributed sampling signals (g) and (h) tj
, Similar to the above-described Nori sampling signals in FIG. 2 (11) to (.), -.Irepel 111 leads to Risan fA state 1m, and low level 10- brings Hall r state.

Hereinafter, the circuit operation of the signal reproducing device shown in FIG. 4 according to the present invention will be explained.

The four-channel distribution signal of POM9'' (not shown) is inputted from the input terminal 2a of the digital-to-analog conversion circuit 2 as a time-divided four-channel digital signal using a generally known method. Then, as described above, the output of the conversion circuit 2 is as shown in FIG.
)&C, it is output as a time-division (concatenated) four-channel signal train.

As described above, the signals of the connected channels are separated by the resampling signals input from the control signal generator 30 to the left and right channel sample hole V circuits 15 and 16, respectively. ) by resampling and hole P.

Next, the signal outputs from the left and right channel resample holes Wt15 and Wt16 are converted into continuous (analog) signals by the corresponding low-pass filters 17 and 18, respectively. be done.

゛However, the corner frequencies of the low-pass filters 17 and 18 are the same as those of the left and right channels.
In each of the P circuits 15 and 16, it is safe to set the frequency to be lower than the frequency H at which the same channel is resampled.

Hereinafter, the left channel resample and hold circuit 15 that resamples the output waveform of the sample Hall V circuit O and the low-pass filter, the Lf and H Lr channels and the Hall P, and the low-pass The case of the filter 17 will be explained with reference to the drawings as an example.

FIG. 6 shows the left channel resample and hold path 15;
3 is an output waveform diagram of a low-pass filter 17. FIG. In the figure, a waveform 25 is a left channel hold signal C"le output from the left channel resample hold circuit 15.
”le 5% s Lr,.

Lfj-...Lfn, Lrn). This signal is the output terminal of the low-pass filter 17, that is, ? , at the L channel output terminal 13, an envelope signal 26 indicating the instantaneous average of the hold signal of the IIf channel and the hold signal of the Lr channel, that is, the combination of the two channels (average value (=Lf + I, r)/2) It becomes a signal.

The same can be said of the output waveforms of the right channel resample and hold circuit 16 that resamples and holds the Rf and Rr channels, and the low pass filter 18 provided corresponding thereto. That is, at the R channel output terminal 14, the combination (average value (Rf
+Rr) /2] signal.

In addition, the control signal generator 30 (FIG. 4), as shown in FIG. 5 (1)
If you generate a sampling signal as shown in the figure below, you can generate a monaural signal, that is, a combination of all channels, by using only one digital-to-analog converter, one resample/hold circuit, one low-pass filter, and one output terminal.
The average value (Lf-)-Rf+Lr-)Rr)/'4) can be reproduced as a signal.

As is clear from the above description, according to the present invention, when playing back a ROM disk or PCM tape, etc. in which audio such as music is recorded in multiple channels of 4 or more channels, in 2 channels or monaural, As previously thought, sample-and-hold circuits, low-pass filters, and other mixers are not required depending on the number of channels before reproduction, and only the number of components required according to the number of channels to be reproduced (VC) is required. It can be easily reproduced without cutting any part of it. That is, according to the present invention, the conventional signal reproducing device can be significantly downsized, simplified, and lowered in cost.

[Brief explanation of drawings]

gg1 diagram is recorded in 4 channels and ft-P OM-7”
A block diagram showing an example of a conventional signal reproducing device for reproducing discs in two channels; FIG. 2 is a timing diagram of a sampling signal to explain the operation of FIG. 1; and FIG. Output waveform diagram showing an example of the output waveform of the sample Hall r circuit and low-pass filter, @4 Figure F
An example of the signal reproducing device of the present invention when reproducing a POM disc recorded in i4 channel with 2 channels y#A
A block diagram showing an example, FIG. 5 is a timing diagram of a sampling signal to explain the operation of FIG. 4, and FIG. 6 is an output waveform showing an example of the output waveform of the sample Hall V circuit and low-pass filter shown in FIG. 4. It is a diagram. 2... Digital analog conversion circuit, 2a... Input terminal, 13... L channel output terminal, 14... R channel output terminal, 15... Left channel resample hole Y times Wg, 16...・Right channel resample hole
& circuit, 17t 18..., low pass filter, 30...
...Patent attorney representing control signal generator Michi Hiraki 1, 13 J Figure 2 23 Figure 4

Claims (2)

[Claims] (1) In a signal reproducing device ili that reproduces in two channels from a POM-recorded recording medium with four or more channels (hereinafter simply referred to as multiple channels), time-sharing of the plurality of channels read from the recording medium is performed. a digital-to-analog conversion circuit for converting a digital signal into an analog signal; a left-channel resample Hall r circuit for resampling and hall-Ping only the outputs of a plurality of left channels among the outputs of the digital-to-analog conversion circuit; Resample only the outputs of the plurality of right channels among the outputs of the analog conversion circuit, Ho 3) 1) Apply a resampling signal to each of the right channel resample Hall Y circuit and the left and right channel Nori sample Hall r circuits. A control signal generator is provided corresponding to the input control signal generator and the left and right channel sample hole r circuits, respectively, and the corner frequency thereof resamples the same channel in each of the left and right channel sample hole r circuits. 1. A signal reproducing device comprising: a low-pass filter set to % or less of a frequency. (2) A digital analog signal that converts time-division digital signals of multiple channels read from the recording medium into analog signals in a signal reproducing device that reproduces monaural data from a recording medium recorded with POM in multiple channels. a conversion circuit; a resample hole circuit that sequentially resamples and holds the output of the digital-to-analog conversion circuit;
A control signal generator that inputs a resampling signal to the resample and hold circuit, and a control signal generator that is provided at the next stage of the resample and hold circuit, and whose corner frequency is equal to the frequency at which the same channel is resampled by the resample and hold circuit. , and a low-pass filter set below A.