SU773937A1 - Device for evaluating communication channel for discrete information transmisiion - Google Patents

Description

one

The invention relates to telecommunications and can be used to assess the suitability of communication channels for transmitting discrete information.

A device for estimating communication channel 5 for transmitting discrete information is known, which contains a discrete signal generator and a serially connected harmonic signal generator, an amplifier, a phase modulator and a matching unit, and a serially connected limiter in the receiving part. phase detector and strobe pulse generator, and successively connected kva.1rator, averaging unit and indicator ij.

However, the known device has low accuracy.

The purpose of the invention is to improve the accuracy of the assessment.

For this purpose, a device for estimating a communication channel for transmitting discrete information, containing a generator of discrete signals and 25 serially connected harmonic signal generator, amplifier, phase modulator and matching unit in the transmitting part, and thirty

A controller, a phase detector and a gating pulse generator, and a quadrant connected in series, an averaging unit and an indicator, a control unit, a key and a signal level selector are inserted, while in the transmitting part the output of the discrete signal generator is connected to the second input of the phase modulator, and in the receiving part, the output of the phase detector through a switch, the control input of which is connected to the output of the strobe generator, is connected to the input of the quad and to the input of the signal level selector; cerned is connected to the second input of the indicator.

The drawing shows a structural electrical circuit of a device for estimating a communication channel for transmitting discrete information.

Claims (1)

The device contains in the transmission part - a harmonic signal generator 1, an amplifier 2, a phase modulator 3, a matching unit 4, a generator of 5 discrete signals, a control unit 6, in the receiving part - a limiting amplifier 7, a phase detector 8, a key 9, a selector 10 The signal level, the generator 11 gates a pulse pulse, the quad 12, the averaging block 13, and the indicator 14. A device for estimating the channel. The connection for transmitting discrete information works as follows. Generator 1 harmonic signal generates a harmonic control signal. Which through the amplifier 2 is fed to one input of the phase modulator 3. The signal from the generator 5 discrete signals through the control block B is fed to the second input of the phase modulator 3. The control unit 6 allows the discrete signal to pass to the second input of the phase modulator 3 only half the duration of the generated control signal. The generated control signal consisting of two parts from the output of the phase modulator 3 through the matching unit 4 is transmitted to the communication channel. The received control signal from the communication channel through the amplifier-limiter 7 is fed to the phase detector 8. At the same time, the amplifier the limiter 7 removes the parasitic amplitude modulation introduced by the communication channel, and the phase detector 8 calculates the phase deviation of the signal from its nominal value. The signal from the output of the phase detector 8 is fed to the key 9 and the strobe generator 11. In the generator 11 of the gating pulses, clock pulses are generated that follow in a time equal to the duration of an elementary parcel of a discrete portion of the control signal and are located at the centers of such parcels. These clock pulses control the operation of the key 9, allowing the phase-detected control signal to pass to the signal level selector 10 and the quadrant 12. The signal level selector 10 determines the number of exceeding the phase deviations of a certain threshold, and the quadr erects the deviation phase squared, then this value is averaged at averaging unit 13. The signal from the selector outputs, 10 and averaging block 13 is indicated on the indicator 14. In contrast to the known, this device allows to evaluate the communication channel by additional parameters (short breaks, level jumps) and to separate the influence of various parameters (additive noise, phase jitter , intersymbol interference), which greatly improves the accuracy of the estimate. This is especially important when transmitting data with multi-position signals at extremely low relative speeds. The device makes it possible to estimate the communication channel in the case of transfer of discrete information on it with any kind of modulation. DETAILED DESCRIPTION A device for estimating a communication channel for transmitting discrete information,. contains in the transmitting part a discrete signal generator and a serially connected harmonic signal generator, an amplifier, a phase modulator and a matching unit, and in the receiving part, a serially connected limiting amplifier, a phase detector and a strobe generator, and the serially connected quadrator, averaging unit and An indicator, characterized in that, in order to improve the accuracy of the estimate, a control unit, a key and a signal level selector are inserted, while in the transmitting part the generator output is a disc The control unit is connected to the second input of the phase modulator, and in the receiving part the output of the phase detector is connected to the input of the quadrant and the selector input of the signal level, the output of which is connected to the second, through the key, whose control input is connected to the output of the strobe pulse generator. indicator input. Sources of information taken into account during the examination 1. Patent of Germany No. 2538536, cl. H 04 L 27/18, 1975.