SU1192147A1 - Method and apparatus for checking digital communication system - Google Patents

Description

The invention relates to telecommunications and can be used to monitor the health of digital communication systems, monitor the health of communication channels from analog input to analog output.

The purpose of the invention is to increase the capacity of a digital communication system by reducing the amount of control information without reducing the accuracy of control.

The drawing shows a structural electrical circuit of the device for the implementation of the proposed method.

The device contains encoder 1,. . block 2 combining signals, first, filter 3, first analog-to-digital converter-logarifmator 4, first selector 5 maximum, block 6 delay, additional comparator 7, block 8 of separation of signals, decoder 9, second filter 10, second analog-digital converter- the logarithm 11, the second allotter 12 maximum, the comparator 13 and the drive 14 pulses.

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The essence of the proposed method lies in the fact that the choice of a reference signal with a maximum (positive or negative) value or the maximum value of a signal modulus. _{On a} certain time interval T ₁ , it is possible to transmit not all information to the receiving side as control information counts on this time interval, but only about one of them. This allows you to reduce the speed of transmission of control information by two orders of magnitude (with an alarm detection time of tens of milliseconds). To implement the proposed control method, it is necessary to synchronize the analysis cycles. Such cycles, synchronous on the transmitting and receiving sides, are naturally found in digital connection systems with almost instantaneous compression. The digital communication channel introduces delays in the propagation of the signal, which can lead to the fact that max. 1192147 4

The signal's maximum, located on the transmitting side at the end of the cycle, on the receiving side * enters the next cycle and as a result of the comparison, a false alarm pulse will be generated. 5 The introduction of the time interval X, during which there is no maximum occurrence, is caused by the fact that the digital communication system consists of analog filters having a group 10 delay time, different at different frequencies, and the delay time even at one frequency It has different instances of filters (technological variation). In this way,. 15, the signal at the receiving side may be delayed relative to the analog signal at the transmitting side for different times. The guard interval 'T _{2 is} chosen greater than the maximum 20 filter delay time, therefore, even if the maximum count is placed at the end of the time interval T and is delayed by the analog channel filters for the maximum time, it does not fall into the next cycle of maximum selection at the receiving side, and the situation when the control count formed on the receiving side is larger than the control count from the transmitting side, it is not considered an emergency count. In digital communication systems, the signal in the digital parts of the encoder and decoder can be delayed for up to tens of milliseconds. This delay is strictly 35

fixed and to compensate for its benchmark it is enough to delay at the same time.

The implementation of this delay can 40 be carried out both at the transmission and at the reception. The difference in the levels of analog signals at the input and the channel output, at which they consider that the channel is faulty, should be 45 more than the sum of the errors of the installation of the residual channel attenuation and the errors of the control circuit. This difference can be taken into account when forming the accident impulse. 50

A device for implementing the proposed method works as follows.

On the transmitting side, the input analog signal in parallel arrives at the input of encoder 1 and at the input of the first filter 3. The first filter 3 suppresses those frequency components of the signal (in the low and high frequencies) for which the phase response of the channel is nonlinear. An analog signal from the output of the first filter 3 is fed to the input of the first analog-digital converter-logarithmat 4, where it is converted into a digital signal. Using the first selector 5 maximum in the time interval T _and is determined by the maximum count of those that are placed on this time interval. As such a sample can be selected a sample with a maximum negative or positive modulo value. At the end of the time interval T ₁ , the contents of the first selector 5 of the maximum are read into delay unit 6. At the end of the next time interval T _{2, the} first selector 5 of the maximum is reset. Next, the delayed control reading from the output of the delay unit 6 is fed to the input of the signal combining unit 2, i.e. combined with a digital information signal. "The above operations are cyclically repeated.

At the reception using the second filter 10 and the second analog-digital converter-logarifmator 11, digital samples of the analog signal are generated from the output of the decoder 9. The reference voltage of the second analog-digital converter-logarithmat 11, from which the quantization thresholds are formed, is less than the reference voltage of the first analog-digital converter-logarithm 4 on the value of the relative errors of the installation of the residual attenuation of the channel, as well as the errors of the circuit! control.

Next, with the help of the second separator 12. the maximum is allocated the maximum count in the time interval

+ T ₂ . At the end of the time interval T _and + T _{2, the} readings of the second highlight 12 are read by gating the comparator 13. Immediately after reading, the second highlight 12 is reset. The comparator 13 using the block 8 separation of the signals compares the reference digital sample extracted from the digital stream with a digital reference

1192147

at the output of the second divider 12 maximum.

If the received reference count is greater than the reference count generated at the reception, the comparator 13 generates an accident pulse. ' The counting of accident pulses at a certain time interval (cycle repeats) carried out by the accumulator of 14 pulses> At the end of the control cycle of 1

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14 pulses reset to zero. The number at the output of the accumulator 14 pulses is compared using an additional comparator 7 with a certain

₅ number and if this number is exceeded, an alarm signal is issued.

The control signals for the blocks in the transmission and reception are the signals of the generator equipment of the digital communication system.

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Claims (2)

1. A method of controlling a digital communication system that includes transmitting the simultaneous formation of a control pulse sequence by filtering an information analog signal and generating an information discrete signal by coding an information analog signal, and then combining the control pulse ослед sequence and information discrete signal, and at the reception - selecting a control pulse sequence and discrete information signal, decoding selected information dirkretnogo signal, its filtering, the formation of the control pulse sequence, comparing it with the selected control pulse sequence and the accumulation of comparison results over a given time interval, characterized in that, in order to increase the throughput of the digital system communication by reducing the amount of control information without reducing the accuracy of the control, on the transmission of information analog signal after filtering is subjected to analog-to-digital conversion with a logarithmic characteristic, of which the total number of samples per interval is. le Τ _ί selected time count with the maximum value, which is taken as control .sformirovannoy pulse sequence, and the formation of the next control pulse sequence start at a time interval, the larger the maximum unevenness of group delay time of the information signal in a communication system, a reception signal is subjected to filtration after analog -digital transformation with a logarithmic characteristic, from ob-. On the time interval T., + T _2, select the sample with the maximum value, which is taken as the generated control pulse sequence, and the formation of the next control pulse sequence begins immediately after the formation of the previous one, comparison of the generated control pulse sequence with the selected control pulse sequence is carried out by determining the difference between them, and accumulate on a given interval For the time being, the number of exceedances obtained by the difference of a given number. with th > 1192147 2. A control device for a digital communication system containing a serially connected encoder and a signal combining unit, the first filter of which is connected to the input of an encoder, and the receiver has a pulse drive, a comparator and a serially connected signal separation unit, a decoder and a second filter; that, in order to increase the capacity of a digital communication system by reducing the amount of control information without reducing the accuracy of control, the first connected logo-digital converter - logarifmator first extractor maximum, which is a control input signal input time interval and the delay unit and on reception - the additional comparator and successively soedi-. The second analog-to-digital converter is a logarithm and the second the maximum selector, the control input of which is an input of time interval signals, while the output of the first filter is connected to the input of the first analog-digital converter logarithm and the output of the delay unit is connected to the second input of the signal combiner, and at the reception the output of the second filter is connected to to the input of the second analogue-digital converter of the -gariformator, the output of the second maximum selector is connected to the first signal input of the comparator, the second signal input and the output of which are connected to Respectively with the second output of the signal separation unit and with the signal input of the pulse accumulator, the output of which is connected to the input of the additional comparator, and the control inputs of the comparator and the pulse accumulator are inputs of the gating signals and the control cycle signals, respectively.