RU1781827C - Method of control of medium valve of signal with phase modulation of carrier - Google Patents

Abstract

Using communication channel quality assessment SUMMARY OF THE INVENTION 1, the received and branched information signal is limited at the level of its specified amplitude limit, amplified this restriction signal in accordance with a specific operator, and subtracted from the received, while comparing with the threshold level. By fixing the excess of the threshold level, it is concluded that the average signal value of 1 sludge is reduced.

Description

The invention relates to radio engineering and can be used to estimate channel quality by changing the average signal value.

An object of the invention is to provide control of decreasing the average signal value.

The drawing shows a structural electrical diagram of a device that implements the proposed method.

The device comprises an indicator 1, a switching unit 2, a control unit 3, a conditionally stable unit 4, consisting of a first adder 5, a limiter 6, two aperiodic links of the first order 7, 8, a second adder 9 and two integrators 10. 11, a threshold block 12 also showed a receiving channel 13 which includes a band-pass filter, 1x) and an amplitude limiter 15

The essence of the invention lies in the fact that after receiving and branching the information signal, it is limited at the level of its specified amplitude limit, amplified in accordance with the operator.

W (p)

TO

(Tr + 1) 2 (Tr-1) the amplified signal is subtracted from the received signal and at the same time it is compared with a constant step-like signal to generate an estimate of whether it is good or bad by the result of changing the sign of the difference signal.

The device operates as follows.

In statics, the circuit of the receiving channel 13 is connected via a switching unit 2 controlled by the unit 3 to the input of a closed conditionally stable unit 4 composed of elements 5-11. An indicator 1 is connected to the output of the first integrator 10 via a threshold element 12. It should be noted that with a strictly linear receiving path 1, there is no influence of interference, including intentional ones, on the fidelity of receiving discrete FM messages. For any one period of T carrying its average value is always zero except (when phase change occurs), when at T the average value is not equal to zero, but has a value of P0 equal to

cl

00

the area of the hatched rectangle by which the elements of the discrete code are formed.

The signal to be monitored enters through the block 2, controlled by block 3, to the input of the first adder 5. When cutting the tops of the total signal in channel 13, the average carrier value decreases in the interval T4. This decrease in the average value leads to malfunctioning of the terminal blocks during the formation of discrete code elements, which affects the quality of FM signal reception. Thus, the value of the average value of the FM signal in the interval of stepwise changes in the carrier phase is important in assessing the quality of the radio channel.

Next, the output signal of the first adder 5 is limited at level B by a limiter b equal to the level of the amplitude limit in channel 13. The limited signal is first amplified by aperiodic links of the first order 7 and 8, each of which corresponds to an aperiodic transfer function

1

where p is the Laplace operator

Then, the limited signal is further amplified by the second adder 9 and two integrators 10 and 11. These blocks constitute an unstable aperiodic unit of the first order. The transfer function has the form W (p) 2 / TP-1. The resistance values of the input resistor and the capacitors of the feedback circuit of the integrators 10 and 11 are respectively equal to each other. Simultaneously with the amplification of the signal, it is inverted. The amplified and inverted signal is fed to the other input of the first adder 5 to subtract it from the previously branched channel signal. The inertia of the closed conditionally stable block 4 corresponds to the period of the monitored carrier of the FM signal

Hodograph AFC of conditionally stable block 4 in the open state in stable W (p)

in its entire form, it has phase stability margins (pzan and amplitudes Hi and Н2. This is possible in the linear mode of operation, when the intensity of the imposed noise is negligible. The controlled average value of AO has the form:

AO J x (t) dt const for | x (t) B, x (g)

about

10

   T4

If x (t.), Then A0 AI,

T

where AI x (t) + x (t)

5o

npn | x (t) + x (t.) AT

A decrease in the average value of the FM signal is equivalent to a decrease in the complex transfer coefficient K Ai / A0

0 of the closed block 4. In such an unstable system, an avalanche-like increase in the controlled signal occurs, which is fixed by the threshold block 12 and displayed using the indicator 1 is valid - not

5 is valid. The threshold level of operation of the threshold block 12 determines the speed of the device implementing the inventive method for monitoring the quality of the radio channel by the value of the average value of the FM carrier.

Claims (1)

Formula of the invention A method for controlling the average value of a signal with a phase modulated carrier, which comprises receiving and branching an information signal, characterized in that 5, in order to ensure control of a decrease in the average value of the signal, the branched information signal is limited at the level of the specified amplitude limiting, amplify it by 0 according to the operator W (P) 07Tfey the amplified signal is subtracted from the branch information signal and at the same time the amplified signal is compared with a threshold level based on the result of the comparison, the average signal value is judged