JPS6320931A - Data transmission equipment - Google Patents

Abstract

PURPOSE:To eliminate the need for the synchronization between a data source and sink and to improve the transmission efficiency by seinding a digital signal of plural channels while applying D/A conversion and decoding the signal to a data signal by A/D conversion at the receiving side. CONSTITUTION:Digital data signals I(1)-1(N) of N channels are inputted to an M-bit (M<=N) D/A converter 13 in a data source 11, where the signals ae converted into an analog data signal according to the logic level of each channel. Furthermore, an A/D converter 16 having the same bit number and the same voltage range as those of the transmission side converts the analog data signal voltage into a digital data signal in a data sink 15. Since an output voltage of the D/A converter 13 use a discrete value at each voltage corresponding to the least significant bit, when the number of channels N to be sent is smaller than the bit number M of the D/A converter 13, the output voltage change width is larger in using the high-order N bits at the input terminal of the converter and it is preferred to prevent transmission errors.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data transmission device that multiplexes and transmits multi-channel digital data signals.

[Prior Art] FIG. 5 is a principle diagram showing a conventional data transmission device as shown, for example, in the Information Processing Handbook edited by the Information Processing Society of Japan. In FIG. (N22) digital signal I (1) to I
A parallel/serial converter 2 having N input terminals 2-1 to 2-N receiving (N) is provided.

4 is a transmission path, 5 is a receiving device, and this receiving device 5 is N
N input terminals 7-1 to ? which output channel digital signals ○(1) to 0(N)? -N is provided with a serial/parallel converter 3.

Note that the digital signals I(1) to I(N).

One of 0(1) to O(N) is a signal for synchronization.

Next, the operation will be explained. N channel input signal I
When (1) to I(N) are input to the transmitter 1, the N-channel input signal circuits (1) to I(N) are switched one after another in temporal order by the parallel/serial converter 2. It is output to the transmission line 4 side. As a result, N channel signals are transmitted to the transmission path 4 in a time-division manner as shown in FIG. In the receiving device 5, the serial signal transmitted by the serial/parallel converter 3 is converted into N
Switch to the output line of the channel one after another. At this time, the switching of each channel is synchronized between the transmitting device 1 and the receiving device 5 so that when the transmitting device 1 sends a signal of the first channel, the signal is output to the first channel in the receiving device 5. In order to achieve this synchronization, for example, a method is used in which a specific start signal and end signal are added before and after the N-channel signal to be transmitted.

[Problems to be Solved by the Invention] However, since such conventional data transmission devices are configured as described above, in order to correctly match the channels on the transmitting device side and the receiving device side, it is necessary to It is necessary to synchronize with the receiving side, and an extra signal for synchronization must be sent in addition to the original transmission signal.Also, since N channel signals are multiplexed by time division, transmission The problem is that it takes time.

This invention was made in order to solve the above-mentioned problems, and the purpose is to provide a data transmission device that can correctly correspond to each channel without synchronization between transmitting and receiving devices and has high transmission efficiency. do.

[Means for Solving the Problems] A data transmission device according to the present invention converts digital data signals of a plurality of channels into analog data signals using a digital/analog converter (D/A converter) in a transmitting device. The data is transmitted using an analog/digital converter (A/D converter) with the same number of bits as the transmitting D/A converter on the receiving device side to restore it to a digital data signal with the original number of channels. be.

[Function] The data transmission device according to the present invention includes, in the transmitting device,
A D/A converter converts the input digital data signal of multiple channels into an analog data signal with a level corresponding to the bit pattern and transmits it, and on the receiving device side,
The A/D converter outputs a digital data signal with a bit pattern corresponding to the input level.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1st
In the figure, 11 is a transmitting device, and this transmitting device 11
are input terminals 12- for receiving N channels (N22) of input digital data signal processing (1) to I (N).
It is provided with an M-bit (M2S) D/A converter 13 having 1 to 12-N.

14 is a transmission line, 15 is a receiving device, and this receiving device 15 receives output digital signals o(1) to O(N) of N channels.
D/A with output terminals 17-1 to 17-N that output
An A/D converter 16 having the same number of bits as the converter 13 is provided.

Next, the operation will be explained. First, in the transmitting device 11, N-channel digital data signals ■(1) to I
(N) is input to an M-bit (M2S) D/A converter 13 and converted into an analog data signal according to the logic level of each channel.

The analog output voltage of the D/A converter 13 is the input N
Since there is a one-to-one correspondence with the combination of logic levels of the digital data signals of the channels, it is possible to transmit all the information of the input digital data signal by transmitting this analog data signal.

On the other hand, in the receiving device 15, this analog data signal voltage is transferred to an A/D converter having the same number of bits and the same voltage range as the transmitting side.
A converter 16 is used to convert the signal into a digital data signal.

As a result, a signal having the same logic level as the input is output to the output channel corresponding to the input.

The output voltage of the D/A converter 13 is the lowest value (1
Since a discrete value is taken for each voltage corresponding to the lower bit (lowest bit), if the number N of channels to be transmitted is less than the number M of bits of the D/A converter 13, the upper N It is preferable to use bits because the range of change in the output voltage becomes larger and transmission errors can be prevented.

It goes without saying that the D/A converter 13 and the A/D converter 16 use their corresponding channels.

Generally, when the input of a D/A converter changes, the output changes, but an A/D converter requires input of a pulse signal to start conversion.

In the conventional device shown in Fig. 5, the signals of each channel are transmitted in a time-division manner, so only one channel's signal is transmitted at each instant, and as a result, the receiving side is out of synchronization with the transmitting side. , transmission cannot be performed normally unless data for N channels is captured, but with the transmission method using this device, all the information of the input digital data signal is included at each instant of the transmitted signal. Because there are
If a pulse signal for starting conversion is added at a cycle faster than the cycle at which the input signal changes, the same pattern as input digital data signal processing (1) to I (N) can be obtained at the output of the A/D converter 16. can.

In the above embodiment, an example was shown in which the analog data output of the D/A converter 13 is transmitted as is, but the output voltage of the D/A converter 13 is changed every voltage corresponding to the lowest bit used. Correspondingly, if the A/D converter has the same voltage range and the same number of bits, the output corresponding to the lower voltage level will be obtained for the voltage value between the discrete values. Since it will be a cover turn, D/A
Rather than transmitting the output voltage of the converter 13 as it is and A/D converting it, it is better to add the voltage within the range where the output pattern of the A/D converter 16 does not change during the transmission. This is preferable because it increases the margin against fluctuations. The voltage to be added is determined by the D/A converter 13 on the transmitting side as described above.
It is necessary that the voltage is less than the voltage change width corresponding to the lowest bit used in
A voltage of about 1/2 is good.

FIG. 2 is a block diagram showing an embodiment in which a voltage adder is provided on the output side of the D/A converter 13. In the figure, 18 is a voltage adder and 19 is an addition voltage source. In addition, the first
The same reference numerals as in the figure indicate the same parts as shown in FIG.

Further, in the example shown in FIG. 2, the voltages are added within the transmitting device 11, but as shown in FIG. 3, the voltages may be added on the receiving side.

In addition, in the embodiments shown so far, an example was shown in which the analog output of the transmission line 11 is transmitted as is, but the transmission line 14
When a change in voltage value is considered, such as when using an optical transmission system for If the receiving device 15 converts the signal back to an analog data signal using a frequency/voltage converter (F/V converter) 21, accurate transmission can be performed without being affected by voltage fluctuations on the transmission path 14.

[Effects of the Invention] As described above, according to the present invention, when transmitting a plurality of channels of digital data signals, the D/A converter converts the signals into analog data signals and transmits them, and the A/D converter on the receiving side Since the configuration is such that the original digital data signal is restored, there is no need to synchronize between the transmitting and receiving devices, and high transmission efficiency can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a data transmission device as a first embodiment of the invention, FIG. 2 is a block diagram showing a data transmission device as a second embodiment of the invention, and FIG. 3 is a block diagram showing a data transmission device as a second embodiment of the invention. FIG. 4 is a block diagram showing a data transmission device as a fourth embodiment of the present invention, and FIG. 5 is a block diagram showing a conventional data transmission device. FIG. 6 is a schematic diagram showing a transmission signal train of a conventional data transmission device. In the figure, 11- transmitter, 12-1 to 12-N-
- Input terminal, 13-D/A converter, 14-transmission line. 15-・Receiving device, 16-A/D converter, 17-1 to 1
7-N-output terminal, 18-voltage adder, 19-voltage source,
20=V/F converter, 21-F/V converter. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (5)

[Claims] (1) A transmitting device that converts digital data signals of multiple channels into analog data signals using a digital/analog converter, and a transmission line that transmits the analog data signals from the transmitting device, and Receiving the transmitted analog data signal from the transmitting device and restoring it to a digital data signal using an analog/digital converter with the same number of bits and the same voltage range as the digital/analog converter in the transmitting device. 1. A data transmission device comprising: (2) Claim 1, characterized in that voltage adding means is provided between the digital/analog converter in the transmitting device and the analog/digital converter in the receiving device. The data transmission device described. (3) As the voltage added by the voltage adding means, a voltage less than the change width of the output voltage when the logic level of the lowest input channel used in the digital/analog converter changes is used. A data transmission device according to claim 2, characterized in that: (4) The voltage added by the voltage adding means is one half of the change width of the output voltage when the logic level of the lowest input channel used in the digital/analog converter changes. The data transmission device according to claim 2 or 3, characterized in that the data transmission device uses voltage. (5) The transmitting device outputs an analog data signal as an analog voltage signal, and is provided with a voltage/frequency converter that converts the analog voltage signal into a frequency-modulated pulse train signal; /Convert the above pulse train signal from the frequency converter to frequency/
5. The data transmission device according to claim 1, further comprising a frequency/voltage converter that converts voltage into an analog voltage signal.