JPS5810036B2 - Multi-frequency signal transmission method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-frequency signal sending method for creating a digitized multi-frequency signal from a plurality of digitized single-frequency signals and sending it out to a transmission path.

Figure 1 shows an example of a multi-frequency signal transmitting device that realizes the conventional digitized multi-frequency signal transmitting system. An adder 2 that adds frequency signals, a multiplier 3 that multiplies the added multi-frequency signal by a level signal, a compressor 4 that compresses the multiplication result, a register 5 that sends out a level signal, and a memory that stores a single-frequency selection signal. 6. Consists of a control circuit 7 that generates various timings and controls each section, and a selector 8 that switches addresses of the memory 6.

FIG. 2 is a time chart showing the relationship between the input signal and the output signal of the multi-frequency signal transmission system to which the present invention is applied.

The single-frequency signal that is the input signal is an analog signal of each frequency that is sampled 8000 times per second, and the sampling results are coded with 16 bits. Normally, audio sampling information is coded with 8 bits, but in this case, addition and multiplication are required. 16 to reduce distortion.
It is said that bit encoding is required.

) 8.192 Mb/s.

The 8 Kb/s clock indicates a sampling period, and single frequency signals within the same period are the same signal.

The output signal line has a time slot of 8 bits,
0=No.

There are 127 and 128, and the 8Kb/s clock is No.
, indicates the beginning of the 0 time slot.

The prior art will be explained below with reference to FIGS. 1 and 2.

The external device writes selection signal data of the multi-frequency signal to be sent into the memory 6.

At this time, the address of the memory 6 and the time slot number correspond, and the external device inputs the time slot number to be transmitted, that is, the address of the memory 6, to the memory 6 via the selector 8.

On the other hand, the control circuit 7 receives an 8Kb/8Kb signal from the outside as shown in FIG.
s and 8.192 Mb/s clock once every two time slots, for example, only in even time slots, and according to the contents of the memory 6, selector 1 is read out.
Two single frequency signals are selected by a and 1b, mixed by adder 2 to create a multi-frequency signal, multiplier 3 multiplies the multi-frequency signal by the level signal sent from register 5, and the compressor 4 compresses the 15-bit signal to 8-bit and sends it to the outside as an output signal.

In addition, according to the delay caused by internal calculation, 8.192
Mb/s and 8Kb/s rerank signals are also delayed and sent to the outside.

In the conventional multi-frequency signal transmission method described above, the input signal is 15 bits, which is computed, compressed to 8 bits, and placed in the time slot, so it is not possible to send the multi-frequency signal in two consecutive time slots. The drawback was that it couldn't be done.

Furthermore, in order to send multifrequency signals to two consecutive time slots, it is necessary to prepare two pieces of hardware, one for even numbered time slots and the other for even numbered time slots, as shown in Figure 1, which requires a large amount of hardware. There was a drawback.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide a multi-frequency signal system that can transmit multi-frequency signals in two consecutive time slots with a small amount of hardware.

The feature of the present invention is that all possible multi-frequency signals are created and stored in advance asynchronously with the time slots, and one externally specified multi-frequency signal is selected and sent out from the multi-frequency signals created in advance at an externally specified time slot. It's about doing.

The present invention will be explained below with reference to FIGS. 2 and 3.

It should be noted that FIG. 3 shows an example of the configuration of a multi-frequency signal sending device that realizes the multi-frequency signal sending method according to the present invention.
Selector 9a+9b for selecting a single frequency signal) Adder 10 for adding the two selected single frequency signals, Multiplier 11 for multiplying the added multifrequency signal by a level signal, Compressor 12 for compressing the multiplication result, Level A register 13 that sends signals, a control circuit 14 that creates various timings and controls each part, an order memory 16 that stores instructions from the outside, a selector 15 that switches the address of the order memory 16, and a buffer memory 18 that stores multifrequency signals. , a selector 17 that switches the address of the buffer memory 18, and a shift register 19 that sends out an output signal.

The external device writes in the order memory 16 the type of multifrequency signal that it wants to send to the time slot according to the address in the order memory 16 that corresponds to the time slot number.

On the other hand, the control circuit 14 performs 8K (
Single frequency selection signals are generated sequentially so as to end within one period of z.

Based on this signal, two single frequency signals are selected via selectors 9a and 9b, and mixed by adder 10 to create a multifrequency signal.

This multifrequency signal is multiplied by the level signal sent from the register 13 in the multiplier 11, and the compressor 12 compresses the 15-bit signal into 8 bits, which is written to the address corresponding to the multifrequency signal in the buffer memory 18.

That is, the buffer memory 18 has the number of words equal to the number of all possible multi-frequency signals, and its contents are 8KH.
It is rewritten once during one cycle of z, that is, once every 125 μS.

The control circuit 14 also controls a selector 15 for each time slot.
According to the contents of the order memory 16, the multi-frequency signal to be sent in that time slot is read out from the buffer memory 18, transferred to the shift register 19, and serially transmitted as an 8.192 Mb/s signal. to the outside.

As mentioned above, a time slot is a process in which all conceivable multi-frequency signals are asynchronously created and stored, and a designated one is selected and sent out from the multi-frequency signals created in advance at a designated time slot from the outside. , it is possible to realize a multi-frequency signal transmission method that can transmit multi-frequency signals in two consecutive time slots with a small amount of hardware.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a multi-frequency signal transmission device that realizes a multi-frequency signal transmission method according to the prior art, and FIG. A time chart showing the relationship, FIG. 3 is a diagram 1177 showing one embodiment of a multi-frequency signal sending device realizing the multi-frequency signal sending method according to the present invention. 9a, 9b... Selector, 10... Adder, 11... Multiplier, 12... Compressor, 13... Register, 14...Control circuit, 15.17...Selector, 16...
...Order memory, 18...Buffer memory,
19...Shift register.

Claims (1)

[Claims] 1. According to instructions from the outside, a multi-frequency signal is created by selectively mixing a plurality of digitalized single-frequency signals, and the multi-frequency signal is sent out in a designated time slot. In the frequency signal transmission method, a memory having the number of words equal to the number of possible combinations of multi-frequency signals is prepared, and the multi-frequency mixture is sent to the corresponding address of the memory every sampling period, asynchronously to the time slot to be sent. The multi-frequency signal is characterized in that the signal data is updated, and at the time of transmitting it to an externally designated time slot, an externally designated multifrequency signal is selected and transmitted from among the multifrequency signals created in advance. Signal transmission method.