JPS6039961A - Service channel transmission method - Google Patents

Abstract

PURPOSE:To attain the transmission of a service channel by adding a pseudo random code instead when at least one channel data signal is interrupted in a multi-value digital radio transmitter. CONSTITUTION:When at least one channel data signal is interrupted among data signals of plural channels inputted to the multi-value digital radio transmitter, pulse interruption detectors D-1-D-5 detect it and switch circuits SW-1-SW-5 interrupt input terminals 1-5 connected to a transmission differential logical circuit T-LOG by using the detection signal. A pseudo random code generator PNG is connected instead and the pseudo random code the same as data signal is fed to the plural channels, allowing to attain the transmission of the service channel.

Description

Detailed Description of the Invention: fat Technical Field of the Invention The present invention relates to a service channel transmission method, and more particularly to a service channel transmission method used in a multilevel digital wireless transmission device.

(2) Prior Art and Problems FIG. 1 is a block diagram of a conventional multilevel digital wireless transmission device, and shows the case of a 16-level orthogonal amplitude modulation system as an example.

In the same figure, for example, a meeting signal (audio) applied to the input terminal 6 for the service channel is 1, and the modulator MOD
-1 to frequency modulate the carrier wave contained therein. The frequency modulated carrier wave is divided into two parts by a hybrid circuit 11-1, and one part is divided by a phase shifter ps so that the phase of the general transmission wave is 90°.
The remaining portion is directly applied to the modulator MOD-3, and the remaining portion is directly applied to the modulator MOD-3.

On the other hand, the four-channel data signals applied to input terminals 1 to 4 are applied to the transmission differential logic circuit T-LOG together with the clock signal applied to input terminal 5, where they are subjected to differential cope ink processing. , binary/four-value conversion circuit 2/4-
For example, a binary data signal that takes a value of 1 or 0 in 1 and 2/4-2 is converted into a 4-value data signal that takes one of the four values of 0.0.5.1°0 and 1.5. Convert to data signal. This four-level data signal passes through a capacitor (not shown) and low-pass filters LIIF-1 and LllF-2 from input terminals (3) and (2) to modulators MOD-3 and MO.
Added to D-2.

The modulators MOD-3 and MOD-2 are composed of a double lance type mixer, and the frequency modulated wave is further pulse-modulated here and then synthesized again in the hybrid circuit H-2, resulting in a meeting signal. After the frequency modulation, a carrier wave (hereinafter abbreviated as composite modulation wave) that has been subjected to 16-value orthogonal amplitude modulation using a data signal is IMized.

This complex modulated wave is converted to the required transmission frequency and level by the transmitter TX and is transmitted from antenna 8 to the other station.

On the receiving side, the received composite modulated wave is amplified and frequency-converted in the receiving section RX, and then applied to the demodulator DEM.

Here, a phase comparator (not shown) compares the multi-level phase point in the complex modulated wave with the phase of the output wave of the voltage controlled oscillator (not shown) included in the demodulator DBH. A voltage corresponding to the phase difference is extracted, and a portion of this voltage is used to control the oscillation frequency of the voltage controlled oscillator so that the phases of the two waves always match.

Then, a part of the demodulated output of the voltage controlled oscillator (which matches the phase of the general transmission wave) is extracted and used to reproduce the data signal from the composite modulated wave.

Further, the remaining part of the voltage corresponding to the phase difference is taken out from the output terminal 7 as a meeting signal.

The demodulator DEFI is configured to block the DC component in order to suppress DC drift and widen the bandwidth of the Haas band circuit.

Figure 2 (al is the modulator MO when the value of 1 or 0 of the data signal applied to input terminals 1 to 4 appears randomly)
The spectrum of the output wave D is shown, and as shown, the upper part is approximately flat and is symmetrical.

However, if the data signals applied to input terminals 1 to 4 in FIG. 1 all have a value of O, for example, then the modulator MOD-
Since MOD-2 and MOD-3 remain in a balanced state, the negotiation signal added thereto is blocked and not sent to the other station.

Also, for example, if the data signal applied to input terminal 1 is
If a data signal with a value of O or 1 is randomly applied to the other input terminals, then the modulator MOD
-3, for example, a binary data signal of 0 and 1.0 is inserted between D
Since the four-value data signal of 0.0.5.1.0.1.5 is added to -2, the spectrum of the output wave of the modulator MOD is as shown in Figure 2 (as an example in tel). It becomes distorted.

On the other hand, demodulator DE? I is configured on the premise that the 4-channel data signals are random or nearly random, so if this condition is not met, for example, as shown in Figure 2 (receiving a complex modulated wave with a distorted spectrum like the one shown in Fig. In this case, the demodulator DE?I cannot match the phase of the demodulated carrier wave and the output wave of the voltage controlled oscillator, making it impossible to reproduce the carrier wave or extract the meeting signal.

As explained above, if at least one channel of the input data signal is interrupted, there is a problem in that it becomes impossible to transmit service channels including meeting signals and the like.

(C1 Purpose of the Invention The present invention was made in view of the problems of the prior art described above, and an object of the present invention is to provide a service channel transmission method that enables transmission of a service channel even if the data signal is cut off. shall be.

(dl) Structure of the Invention The object of the above invention is to transmit at least one of the data signals of a plurality of channels input to a multilevel digital wireless transmission device.
When the data signal of a channel is disconnected, the disconnection of the data signal is detected, and based on this detection signal, the output from the pseudo-random code generator is input to the multilevel digital wireless transmission device instead of the data signal of the plurality of channels. This is achieved by providing a service channel transmission method characterized by:

tel Embodiment of the Invention FIG. 3 shows an example of a block connection diagram for implementing the invention.

In the figure, D-1 to D-5 are pulse break detectors, C
0NT is the control unit, PNG is the pseudorandom code generator, 5W-1 to 5W-5 are the Swissoji circuits, and T-
LOG connects the transmit differential logic circuit to 2/4-1 and 2/, l
-2 is a binary/four-value conversion circuit, LPF -1 and LPF
-2 indicates a low-pass filter, Mo1) indicates a modulation section, TX indicates a transmitting section, and 1 to 6 indicate input terminals, respectively.

Note that the same parts as in FIG. 1 are given the same reference numerals, and the receiving section is omitted because it is the same as in FIG. 1.

These blocks are connected as follows.

In FIG. 3, input terminals 1 to 5 are switch circuits 5W-1 to S-5, transmission differential logic circuits T-1, OG,
The modulation unit M
The input terminals 1 to 5 are connected to the input terminals of the control unit C0NT via pulse break detectors D-1 to D-5, and another input terminal of the control unit C0NTO is connected to the input terminal 5 of the control unit C0NT.
, the first output terminal is connected to the second input terminal of the switch circuit needle -1 to 5W-5, and the second output terminal is connected to the switch circuit 5W.
-5, the third output terminal is connected to the switch circuit 5W-1 to 5W-5 via the pseudo-random code generator PNG.
They are respectively connected to the third input terminals of W-4.

The output terminal of the modulator MOD is connected to the antenna 8 via the transmitter TX, and the input terminal 6 is connected to another input terminal of the modulator MOD.

The dotted line portion is a circuit added to implement the present invention.
A detailed explanation of the operation of the other portions will be omitted since it has been explained in detail in the conventional example, and the operation of the additional circuit will be explained.

In the same figure, a pulse break detector 1 connected to input terminals 1 to 5 detects the presence or absence of data signals applied to input terminals 1 to 4 and black and white signals applied to input terminal 5. )-1 to 1)-5.

If any one of the four input signals is disconnected, the pulse disconnection detectors I]-1 to D-4 detect this, and the output signal of this detector is used to detect the switch circuit needles -1 to 5W. -5
disconnects the input terminals 1 to 5 connected to the transmitting differential logic circuit T-LOG and uses the pseudo-random code generator PNG instead.
Connect.

Therefore, the pseudo random code is
W-4, transmission differential logic circuit T-LOG, binary/four-value conversion circuits 2/4-1 and 2/4-2, low-pass filter LPF
-1 and LPF-2 and is applied to the modulator MOD, where a composite modulated wave is created. This complex modulated wave is then sent through antenna A to the receiving side.

Note that the output wave of a voltage controlled oscillator (not shown) included in this control unit C0NT and in phase synchronization with the clock signal applied from the input terminal 5 is used as a clock signal to the pseudo random code generator PNG and the switch. Circuit S-5
It is added to the transmission differential logic circuit T-LOG via.

When the clock signal applied to the input terminal 5 is cut off, the voltage controlled oscillator in the control unit C0NT runs free, and the output wave is sent to the pseudo random signal Kano generator P.
NG and switch times I? 85W-5 to the transmission differential logic circuit T-LOG.

(fl As described in detail, according to the present invention, when at least one channel of input data signals of a plurality of channels is disconnected, this is detected and data is transmitted to the plurality of channels. By adding a pseudo-random code with the same randomness as the signal to the multilevel digital wireless transmission equipment,
It is possible to enable the transmission of service channels.

[Brief explanation of the drawing]

FIG. 1 is a block connection diagram of a wireless transmission device using 16-value orthogonal amplitude modulation as an example of a conventional multilevel digital wireless transmission device, and FIG. 3 each shows an example for implementing the present invention. In the figure, D-1 to D-5 are pulse break detectors, C
0NT is the control unit, PNG is the pseudo-random code light 71.
:jlj, S-1 to 5W-5 are each switched once
T1 and OG represent the transmission differential logic circuit, MOD represents the modulation section, and 'I'X represents the transmission section. 17 miles)

Claims (1)

[Claims] When at least one channel of data signals of a plurality of channels inputted to a multilevel digital radio transmission device is disconnected, the data signal disconnection is detected, and this detection signal is used to detect the data signal of the plurality of channels. A service channel transmission method characterized in that, instead, an output from a pseudo-random code generator is manually input to the multilevel digital radio transmission device.