SU555550A1 - Device for automatic selection of working frequencies with spaced reception - Google Patents

Description

(54) DEVICE FOR AUTOMATING OPERATING FREQUENCIES AT DIFFERENT RECEPTION

to the second inputs of which a time sensor is connected.

The unit for measuring the fading rate is made in the form of a series-connected detector envelope of video pulses, a high-pass filter, an integrator, and a controlled threshold element.

In the drawing, e is a block diagram of the proposed device.

The device dp auto-selection of working frequencies with spaced reception contains sets, N is the number of diversity branches that are connected in parallel to the input of bandpass filters 1-1 - 1- N (in drawing 1-1 / 1 .... - band-pass filters of even frequencies, respectively 1 ., .. Yzetvi, 1-1 / 2-1-N / 2-band filters of odd frequencies, respectively, 1 .... N branches), each connected through a corresponding amplitude detector 2 (2-1 / 1, 2-1 / 2 ..... 2-N / 1, 2-N / 2 to block 3 for selecting the optimal frequencies, to the outputs of which block 4 is coded for the numbers of the selected frequencies, two channels from the sequence flax connected in each element 5 (5-1, 5-2 and adder 6 (6-1, 6-2), unit 7 for measuring the speed of fading, the third element AND 8, to another input of which is connected unit 9 for measuring the reliability transmission of commands, and shaper 10 code fixed frequencies.

The unit for measuring the speed of fading 7 is made in the form of serially connected detector of the envelope of video pulses 11, high pass filter 12, integrator 13 and controlled threshold element 14.

The unit 9 for measuring the reliability of command transmission is made in the form of serially connected error counter commands 15, the input of which is the input of the block KA, and trigger 16, to the second inputs of which time sensor 17 is connected.

Between the output of one of the amplitude detectors 2 and the second inputs of the adders 6 of each channel are connected in series the unit 7 for measuring the fading speed, the third element 8, the output of which is also connected to the second inputs of elements 5 of each channel, and the fixed frequency code generator Yu.

The proposed device works as follows.

Probing signals, for example, even and odd frequencies, are sent to bandpass filters 1, where they are selected, and then to amplitude detectors 2. In block 3, to select the optimal frequencies, select even and odd optimal signals, which are then encoded in blocks

ke 4 for coding selected frequency numbers.

In the envelope detector of the video pulses 11, the envelope of the amplitude modulated pulses is extracted. With fast fading, this envelope contains spectral components with a frequency of more than 30 Hz, which select a high-pass filter 12, integrate over several cycles in integrator 13 and is fed to a controlled threshold element 14, the threshold level of which depends on the AGC voltage. With large signals, the threshold level of the controlled threshold element 14 increases. Due to this, the threshold threshold overshoot is determined by the speed, the fetzing and the map depends on the level of the water: go: 1X clock / s,

Thus, prrb be .strom fsdigg- :; At the output of the controlled threshold element 14, a signal arises in the form of a positive potential. If at the same time the counting, command failures checkbox 15 fixes low confidence in the transmission of commands, then from trigger 16 to the input of the third element I 8 will also arrive put; and potential, a control signal will appear at its output, which will switch synthesizers (not shown) to the operation at fixed frequencies, allow generation of the fixed frequency code B by the shaper 10 of the fixed frequency code and prevent transmission from block 4 to encode the selected frequency numbers in the elements and 5.

As a result of these operations, the transmitter begins to emit information at two fixed frequencies, and fourfold diversity reception is realized at the receiver.

They will suggest: the device has high reliability with zi under fast signal fading.

Claims (3)

1. A device for automatic selection of working frequencies with spaced reception, containing N sets, where N is the RUNFLAY branches connected in parallel to the input of bandpass filters, each connected via a corresponding amplitude detector to the unit for selecting the optimal frequencies to the outputs of which are connected to the unit for coding numbers selected frequencies, characterized in that, in order to increase the reliability of communication during fast fading of a signal, two ka are connected to the outputs of the unit to encode the numbers of the selected frequencies ala serially connected in each element And and adder, and between the output of one of the amplitude detectors and the second inputs of the adders of each channel are connected in series the unit for measuring the fading speed, the third element And, to the other input of which is connected the unit for measuring the reliability of command transmission, and This output of the third element And is also connected to the second inputs of the elements AND of each channel. 2. The apparatus of claim 1, wherein the unit for measuring the reliability of command transmissions is performed in a PID of a serially connected instruction failure counter, the input of which is the input of the unit, and a trigger, to the second inputs of which a time sensor is connected. 3. The device according to claim 1, characterized in that the unit for measuring the fading speed is made in the form of serially connected video pulse envelope detector, high-pass filter, integrator and controllable threshold element. Sources of information taken into account in the examination; 1. USSR author's certificate No. 289517, M Cl. H 04 B 1/66, 1969 (prototype).