JPS585539B2 - Carrier communication method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides n small transmission bands having the same frequency band.
The present invention relates to a carrier communication system in which after frequency conversion is performed using n modulators, unnecessary side bands are removed using n p-wave modulators, and the result is integrated multiplexing and transmission.

In carrier communication systems, band waves and interference generation waves (distortion, residual carrier waves, etc.) are generated from the modulator used for frequency conversion, so in order to suppress these waves, one-to-one transmission is performed after each modulator. A filter is connected in correspondence (in the case of reverse demodulation, a filter is connected before each modulator).

Since the filters connected to each modulator account for a large proportion of the price of the transmission system, when designing carrier communication systems, attention is paid to how to reduce the type, quantity, and cost of the filters. .

Figures 1 and 2 are diagrams explaining the conventional conversion method.
1 to 5 show the frequency allocation, and FIG. 2 shows a block diagram of the transmitter.

In the figure, F1 to F3 are filters, R1 and R2 are wave removers, M1 and M2 are modulators, TI and T2 are hybrid transformers, and O1 and O2 are carrier wave generation sources, respectively.

In FIG. 2, channels CHB-CHD have the same configuration as channels CHA, and the front group P
G2 to G4 are omitted because they are completely the same as the front group PG1.

Further, although FIG. 2 only shows the transmitting side, the receiving side is omitted because it has exactly the same configuration as the transmitting side.

In Figures 1 and 2, 0.2 to 3.05KHz
After each of the four audio signals (FIG. 1) having a band of
Hz, 20.85KHz and 21.15KHz (first
2), and unnecessary sideband waves and residual carrier waves are suppressed by each channel carrier wave remover and channel bandpass filter F2 (FIG. 1, 3).

The output of filter F2 is integrated by hybrid transformer T1 to form a front group frequency band of 12.10 to 23.90 KHz.

The front group frequency band consisting of the four audio signals obtained in this way is further divided into required front group carrier waves of 84 KHz, 96 KHz, and 108 KHz by the respective front group modulators M2.
and i20KHz (Fig. 1, 4), unnecessary band waves and residual carrier waves are suppressed by each front group bandpass filter F3, and then integrated by a hybrid transformer T2 to convert the odd-numbered and even-numbered A basic group frequency band of 60.1 to 107.9 KHz is obtained in which the frequency arrangement of the communication paths is opposite to each other (FIG. 1, 5).

On the receiving side, 60.
The basic group frequency band from 1 to 107.9 KHz is converted into 16 audio frequency bands.

Note that the pilot frequency remover R2 is for blocking a band corresponding to the pilot frequency.

In such a conventional system, one type of voice band filter F1, four types of communication path carrier wave removers R1 corresponding to communication path carrier waves A to D, and four types of communication path bands corresponding to channels CHA-CHD are used. A total of 14 types of filters are required, including a P-wave filter F2, four types of front group bandpass filters F3 for PG1 to PG4, and one type of pilot frequency remover R2.

Furthermore, as is clear from the frequency arrangement in Fig. 1,
Frequency interval between each channel is 100Hz in the low frequency part
, since the high frequency portion is only 200 Hz, the channel bandpass filter F2 must have extremely steep stopband attenuation characteristics.

In this way, in conventional conversion systems, there are many types of F-wave converters used in the converter, and moreover, the P-wave converters include:
Since steep stopband attenuation characteristics are required, the device has the disadvantage of being expensive.

An object of the present invention is to provide a carrier communication system that eliminates the above-mentioned drawbacks.

Next, the present invention will be explained in detail with reference to the drawings.

3. FIGS. 1 to 10 are frequency allocation diagrams for explaining one embodiment of the present invention, and FIG. 4 is a block diagram thereof.

In Fig. 4, F1 to F4 are filters, R1 and R2 are wave removers, M11, M12, M2, and M3 are modulators, and P1 and P
2 is a +90 phase shift circuit, O1 to O3 are carrier wave generation sources, and TI is a hybrid transformer.

In addition, in FIG. 4, channels CH2 to CH16
has exactly the same configuration as CH1, and the receiving side configuration is also the same as the transmitting side shown in FIG. 4, so it is omitted.

In Figures 3 and 4, 0.2 to 3.05KHz
After each of the 16 audio frequency bands (Fig. 3 1) passes through an audio band F-wave unit F1, a pre-modulated carrier wave of 127.85 KHz (
3), unnecessary band waves and residual carrier waves are suppressed by the frequency inversion, the pre-modulated carrier wave remover R1 and the channel bandpass filter F2.
It is converted into the front group frequency band (hereinafter abbreviated as front group) of z (FIG. 3).

Of the 16 front groups obtained in this way, those corresponding to even-numbered channels are sent to the communication path modulator M2 to generate required even-order communication carrier waves (191, 197, 203, 209,
215, 221, 217, 225KHz) (Figure 3 4)
is converted into a desired group frequency band of 60 to 108 KHz and integrated.

(Figure 3 5). Also, those corresponding to odd-numbered channels are the required odd-numbered channel carrier waves (275, 281,
287,293,299,305,311,317KH
z) (Fig. 3 6), 144.1 to 188.95K
After being converted to the Hz band and integrated (Fig. 3, 7),
The unnecessary upper sideband etc. are suppressed by the odd-order group low-pass filter F3, and the odd-order group carrier wave is further used by the odd-order group modulator M3 to reach the desired band in the group frequency band of 60.1 to 107.9 KHz. (Fig. 3, 9).

The even-order group and odd-order group obtained in this way are integrated by the hybrid transformer T1, and unnecessary sidebands outside the basic group are blocked by the group bandpass filter F4, and the frequency arrangement of the odd-numbered and even-numbered transmission bands is performed. are facing each other 6
A fundamental group frequency band of 0.1-107.9 KHz is obtained (FIG. 3, 10).

On the receiving side, 60
．． Sixteen audio frequency bands are converted from the basic frequency band from 1 to 107.9 KHz.

By adopting the above configuration, the types of filters required are one each of voice band filter F1, premodulation carrier wave remover R1, front group band F wave filter F2, and odd-order group filter F1. A total of six types of bandpass filter F3, group bandpass filter F4, and pilot rejector R2 are required, and the number of types can be significantly reduced compared to the conventional system.

Also, the high stopband attenuation required for channel bandpass filters is significantly reduced by using a phase difference modulator.

Furthermore, an odd-order group low-pass filter F3 and a group bandpass filter 4F
As can be seen from the frequency arrangement, the unnecessary sidebands and unnecessary carrier waves that these filters should suppress are located far away from the desired band, so the stopband attenuation at the band limit is gentle, which is the same as before. The cost of these p-wave devices can also be reduced compared to the conventional method.

As described above, the present invention can reduce the types and costs of filters used in a transmission system by dividing them into small groups of odd-order groups and even-order groups, and converting and integrating them. It greatly contributes to mass production and economy.

[Brief explanation of drawings]

Figures 1 to 5 and 2 are frequency allocation and block diagrams according to the conventional system, Figure 4 and Figure 3
10 is a frequency arrangement and a block diagram of an embodiment of the present invention. In Fig. 2 and Fig. 4, F1, F2...
Filter, Rl, R2... Wave remover, M1, M2.
...Modulator, T1, T2...Hybrid transformer, O1, O2...Carrier wave generation source.

Claims (1)

[Claims] 1 In a carrier communication system in which n transmission bands having the same frequency band are frequency-converted by n modulators installed correspondingly, and then unnecessary waves are converted into P waves using n F-wave devices and integrated. , the n transmission bands are amplitude-modulated with a first carrier wave and converted into n front groups, and the even numbers of the n front groups are converted into two second bands having different frequencies. Amplitude modulation is performed with a carrier wave to convert it into a first partial transmission band, and each of the odd numbers in the front group is amplitude modulated with a third carrier wave having a mutually different frequency and converted into a second partial transmission band. and converting the second partial transmission band into a third partial transmission band by amplitude modulating it with a fourth carrier wave, and combining the first and third partial transmission bands to obtain the n transmission bands. 1. A carrier communication system characterized in that frequency arrangements of even-numbered transmission bands and odd-numbered transmission bands of the above are arranged so that they face each other.