JPS6062250A - Pcm converting device - Google Patents

Abstract

PURPOSE:To obtain a small-sized device with small power consumption by sampling a signal at different time once more which is sampled previously in a digital audio circuit having plural channels, and performing mutual conversion between an identical-time sampled signal and an alternate standardized signal. CONSTITUTION:Control signals 501, 502, 503, and 504 control sample holding circuits 401, 402, 201, and 202 for identical-time sampling; ''H'' shows sampling and ''L'' indicates a holding state. Then, analog signals of an L and an R channel sampled at the same time t1 are converted into digital values by one A/D converter 1. When alternate sampling is performed, the sample holding circuits 401 and 201, and 402 and 202 are applied with the control signals 501 and 504 respectively. Then, the R-channel signal sampled at time t1 and the R-channel signal sampled at time t3 are converted into digital values by one A/D converter 1.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a PCM conversion device, and particularly to a PCM conversion device suitable for converting sampling times between simultaneous sampling and alternating sampling.
(Regarding the conversion device.

[Backbone of the invention'I,'t]

In the conventional PCM format, the sampling time alternates between the L channel and the R channel. Furthermore, in order to simplify one circuit, the PCM system had alternate sampling output.

Therefore, the conversion of data between different formats and the above F3
There were problems such as when outputting simultaneous sampling signals with the pi simplification device.

The above will be explained using the waveform diagram in FIG.

Figure 1 α is an example of simultaneous sampling, and the black circles in Figure 1 indicate the values of sample points. The broken line is a drum shape when simultaneously sampled data is output by alternate sampling.

Figure 1 is an example of alternate sampling, and the black circles in the figure indicate the values of sampling points. The breaks in the figure are waveforms when alternately sampled data is output with simultaneous sampling.

As mentioned above, in both cases, LIIR2 in the original signal
It has different characteristics than between channels.

Here, if the number of input analog signal channels is 2 in a general PCI/' device, only one A, D Ci or DAC can be used in the analog to digital conversion circuit and the digital to analog conversion circuit. 1 knife 6c)V
A form of alternating sampling is used in each case.

This causes the above-mentioned problems. That is.

It is possible to use alternately sampled data in place of simultaneously sampled data or to output simultaneously simultaneously sampled data and alternately sampled data at L°C.

FIG. 2 is a block diagram of the analog-to-digital converter. Figure 2 α shows a simultaneous sampling circuit for L and R2 channel signals, where the L channel signal 6 is converted into a digital signal 7 by the sampling holding circuit 201 and the analog-to-digital converter '1, and the R channel signal 4 is sampled. The digital signal holding circuit 202 and the analog-to-digital converter 1 convert the digital signal fJ into a digital signal 8, and from these digital signals 7.8, an alternate output 9 is obtained by the switching circuit M2.

The second tooth is an alternating sampling circuit for L and R2 channel signals, and the L channel signal 3 and R channel signal 4 are switched by the switching circuit 5 via the sampling hold-8201 and 202, respectively, and the alternating signal 6 is converted by an analog-to-digital converter 1, and a digital signal 1o is output.

FIG. 3 is a block diagram of the digital-to-analog conversion section. FIG. 3 α shows the simultaneous sampling output circuit of L-R2 channel No. 4g, and the L channel signal 11 is converted into an analog signal 1 by the digital-to-analog converter 13 and the sampling holding circuit 301.
The R channel signal 12 is converted into an analog signal 15 by the digital-to-analog converter 13 and the sampling/holding circuit 602, and is outputted. Figure 3 Suha L
・This is an alternate sampling output circuit for R2 channel signals.

The L-R alternating signal 16 is converted into an analog signal 17 by the digital-to-analog converter 13, and divided into an L channel analog signal 19 and an R channel analog signal 20 by sampling and holding circuits 301 and 302 and output.

[Purpose of the invention]

An object of the present invention is to provide a PCM conversion device having a sampling time conversion function.

[Summary of the invention]

The present invention is to sample a signal once sampled again at another time.

[Embodiments of the invention]

As an embodiment of the present invention, an analog-to-digital converter 7a capable of simultaneous sampling and alternating sampling is described below.
It is shown in the figure and explained using Figure 5. 401. , 402
405 is a sampling holding circuit, and 405 is a control circuit.

The operation of sampling at the same time and converting it alternately using one analog-to-digital converter will be explained.

Reference numerals 501, 502, 503, and 504 indicate control # signals of the sampling and holding circuits 401, 402, 201, and '202, respectively, which indicate the sampling state when it is High and the holding state when it is Low. 505 is a control signal for switch 5. The L channel signal is sampled and held by a circuit 401. The R channel signal is sampled and held in the holding circuit 402 at the same time t. Sampling starts at tl, the state moves from sampling to a holding state at tl, and the hani at time tl is held. At the same time, the sampling holding circuit 201 also receives the control signal 503.
When operated at t, the value at time t is stored in the sampling holding circuit 20.
It is also held at 1. The value of the L channel held in this 201 is set to 1 by the switch 5. At the time of ~tll, in addition to the analog digital converter 1, digital [IC] conversion is performed. At t2, the value of the R channel held at 402 at tl is resampled by the sampling/holding circuit 202 and held at tl, but this value is the same as the value held at tl. This 2
The value of the 7j R channel held at 02 is added to the analog-to-digital converter 1 and converted into a tintal value by the switch 5 at 5Ij intervals from t3 to tr.

L and R sampled at the same time at time t,
The channel analog a/signal can be converted into a tintal value using one analog-to-digital converter 1.

Next, the case of alternate sampling will be explained.

A control signal 501 is supplied to the sampling and holding circuits 401 and 201.

A control signal 504 is applied to the sampling and holding circuits 402 and 202. Compared to the case of time sampling, the control signal for the sampling control circuit 4020 is changed to 504.

Sampling begins at time 201 through the sampling holding circuit 401, and the analog value at time t is held. The switch 5Vc converts the R channel signal into a digital image at time t, tyt, by adding it to the analog/tintal converter 1.The R channel signal is passed through the sampling and holding circuit 402 and starts to be converted into a digital image at time t2, t, The analog value at time tj is held.The value of the R channel held at 202 is changed to analog value a at time t and tj by switch 5.
It is added to digital converter 1 and converted into a digital value. That is, the L channel signal sampled at time tl and the R channel signal sampled at time t can be converted into tintal values by a 1 wA analog fist digital converter f18 device 1.

As explained above, by switching the control gI of the sampling/holding (9) path 402 between 502 and 504, simultaneous sampling and alternating sampling can be switched. In addition.

If the control signals 401 and 201 are the same for both simultaneous sampling and alternate sampling, 401- may be omitted.

Next, as another embodiment 911 of the present invention, a digital-to-analog converter that can perform simultaneous sampling and alternate sampling using a single digital-to-analog converter is shown in FIG. 6, and FIG. ℃Explain. 601 and 602 are sampling and holding circuits, and 603 is a control circuit. 701 is a data input timing waveform to the digital analog converter 13, and here it is assumed that data of the R channel is input at high and low channels.702 to 705 are control signals for the sampling and holding circuits 301, 12, 601, and 602. Set to ELgh to sample, and set to Low to hold.

First, let us consider the case of reproducing L channel and R channel signals whose data is sampled at the same time.

Time T. The data of the TL channel is applied to the digital to analog converter 13. At time T after the analog output of the digital-to-analog converter 16 reaches a value corresponding to the digital input, the sampling holding circuit 601 outputs that ivi
is sampled and held until the next Tr. The R channel data is applied to the digital-to-analog converter 15 at T,
The value is sampled by the sampling holding circuit 601 at the time after the first shift corresponding to the analog output or digital input. N-T4bA Sumuhemaru et al. L to Hashimoto I. (b) Paths 301 and 302 to sample holding circuit 60
1 and 602, each L channel,
Obtain the output of the R channel. That is, since the outputs of both channels change at T, the data of the L and R channels sampled at the same time can be converted into analog values by one digital-to-analog converter.

Next, consider the case of reproducing alternately sampled L channel and R channel signals. The control signal for the stringing holding circuit 6010 is changed from 704 to 702.

At time l'o, the data of the L channel is applied to the digital analog converter 16, and at time T1 after the analog output reaches a value corresponding to the digital input, the value is sampled by the sampling and holding circuits 601 and 301. Next time T]'
! The data of the R channel is applied to the Tyntal analog converter 16 at T, and the value corresponding to the analog output or digital input is reached at time T4.
Then, the sampling holding circuits 602 and 602 hold the myx until the time η of the alternate sampling and output it at °C. That is, time T
It is possible to correspond to alternate sampling in which the output of the L channel changes at 1 and the output of the R channel changes depending on the time. Note that if the control signals 602 and 602 are the same for both simultaneous sampling and alternate sampling, 602 may be omitted. Further, instead of the sampling and holding circuits 301 and 502, the same effect can be obtained by using a sampling circuit that passes the signal during the pressure sampling period and cuts off the signal, such as by grounding, during the holding period.

〔Effect of the invention〕

According to the present invention, in digital audio having two or more channels, a signal sampled at the same time can be converted to an alternately sampled signal, or a signal sampled alternately can be converted to a signal sampled at the same time.

It becomes possible to exchange digital data with different sampling timings. In addition, since it is possible to switch between simultaneous sampling and alternating sampling, one digital-to-analog converter or analog-to-tintal converter can be used for both simultaneous sampling and alternating sampling systems instead of two. This also has the effect of making it possible to reduce costs, reduce size, and save power.

[Brief explanation of the drawing]

Figure 1 is a sampling waveform diagram, Figure 2 is the configuration of a conventional analog-tintal converter, and Figure 3 is a diagram of a conventional tintal converter.
FIG. 3 is a configuration diagram of an analog converter. Fig. 4 is a block diagram showing an embodiment of the invention, and Fig. 5 is a block diagram showing an embodiment of the invention.
FIG. 6 is a block diagram showing another embodiment of the present invention, and the seventh quotient is for explaining the operation of FIG. 1...Analog/tinal converter 16...Tinttal/analog converter 201.202
,501,! 102,401.402,6IJ1,6
02...Sampling and holding circuit 405.603...Control circuit agent Akio Takashi Figure 1 Z Figure 3 3θ2 zuθl 4th Figure 6 6 Figure q

Claims (1)

[Scope of Claims] 1. An analog system that has a gap between a sampling holding circuit that samples and holds a plurality of analog signals at a certain time and an analog-to-digital conversion circuit that converts the held analog signals into digital signals. A digital converter, a digital-to-analog conversion circuit that converts a digital signal to an analog/multiple signal, and a converted analog. In a PCM conversion device that includes one or both of the digital-to-analog conversion devices and a resampling circuit that switches and outputs a sampling signal to a plurality of outputs, the output of the sampling holding circuit is The outputs of the first sampling holding circuit and the digital/analog converting circuit are sampled and held at four or different times from the sampling time of the first sampling holding circuit and the outputs of the digital/analog converting circuit are resampled. PCM conversion characterized by providing a second sampling holding circuit that samples and holds the sample at the same or different time as the sampling time of the sampling circuit and outputs it to the resampling circuit. Device. 2. In the PCM conversion device according to claim 1, the first and second sampling times are controlled by a signal that controls whether or not to change the sampling times of the first and second sampling holding circuits. Sampling time 'a of the holding circuit - The % characteristic is that it is possible to select whether to change or not to change P.
CM conversion device.