SU785986A1 - Pulse selector - Google Patents

Description

(54) PULSE SELECTOR

The invention relates to a pulse technique, in particular, to pulse selectors by period, and can be used in radio devices to distinguish a periodic sequence of pulses from the background noise. A time selector is known that contains keys, a frequency divider, a strobe generator, and a control pulse generator l. A disadvantage of the known device is the low reliability of selection. The latter is due to the fact that in the presence of gaps in the selectable sequence of pulses, this time selector gives failures, expressed in an increase in the number of gaps at the output compared to the number of gaps at its input. A pulse selector is also known, which contains a scaling device, a prohibition element, as well as a sequentially connected trigger, the first OR element, a half-cube shaper, a second OR-element, a delay element, a gates-shaper, an output AND element, the other input of which is connected to the pulse selector input, one input trigger and reset input of a sweeper, the input of which is connected to the output of the gate driver. The other input of the trigger is connected to the first output of the counting device, the second output of which is connected through a prohibition element to the second input of the second OR element, and the second input of the prohibition element is connected to the output of the half-shaper and the second; the input of the first OR element is connected to the output of the pulse selector 12. The disadvantages of the selector are the complexity, expressed in a large number of elements necessary for its construction, low reliability of selection under interference conditions, due to two factors and, firstly, in case of interference, entering the strobe, after the arrival of a selectable pulse, this interference arrives at the output of the pulse selector. secondly, when counting by the scaling device the number of passes of the selectable pulses, any interference received at the input of the pulse selector resets the scaling device, eliminating the accumulated result. The gap of the invention is improving the reliability of selection. To do this, a pulse selector containing a scaler and an OR element connected in series, a delay element, a gate driver and an AND element whose second input is connected to the input bus, an output to the output bus, the first input of the OR element and the first input of the counting device, and the second The input of which is connected to the first input of the element I, and the output to the second input of the delay element, a device for selecting the first pulse is entered, the first input of which is connected to the input bus, the second input to the output of the counting device TWA, and the output is with the second input of the OR element, and the second input of the gate driver is connected to the output of the AND / and the other output to the third input of the OR element. FIG. 1 is a structural electrical circuit diagram of the device of FIG. 2 - time diagrams. The pulse selector comprises a first pulse extraction device 1 connected in series, an element OR 2, a latch element 3, a gate generator 4, an AND 5 element, the other input of the AND 5 element being connected to the input bus and one of the inputs of the first pulse extracting device 1, the other input of which is connected to the reset input of the element 3 and the output of the device 6 of the recalculating The output of the imaging device 4 is also connected to the input of the device 6, the reset input of which is connected to the output bus, the output of the And 5 element, the reset input of the imaging equipment 4 and the second input element house OR 2, kotorog third input coupled to the output of the intermediate 4. Consider the operation timing diagram of the pulse selector (FIG. 2), which shows signals for the circuits a, b, c, 3, e, which is also marked in Fig. 1. The diagram shows the following typical cases of operation: the pulse selector is triggered by the first input pulse, the second input pulse hits the first half of the gate, the third input pulse hits the second half of the gate, the fourth input pulse passes, and the input pulse hits the middle of the gate . For the second and third input pulses, the dotted lines mark the moment of their expected arrival, corresponding to the midpoints of the strobes. The first, a pulse, is sequenced by device 1 and, through element OR 2, starts element 3 (Fig. 2), which delays the signal by the value of where T is the expected pulse period; strobe width Thus, after time T from the moment of arrival of the first pulse, shaper 4 starts up, which opens element 5. The next pulse from the input bus no longer passes through device 1, but passes through open element 5 and 5 to the output when the condition of this pulse enters the strobe. Let the second pulse of the sequence hit the first half of the strobe (Fig. 2), then it comes through an AND 5 element open at this time to the output. From the output, it resets the driver 4 and, through the element OR 2, starts element 3, which again counts time 1 /, starts the driver 4, etc. Shaper 4 forms a strobe with a duration of -t and marks the middle of the strobe with a signal at its intermediate output. At the moment of resetting the former 4, the gate is interrupted, closing element 5. And. If any of the pulses in the sequence, for example, the third (Fig. 2), falls into. the second half of the strobe, element 3 is first triggered by a signal in the middle of the strobe; arriving from the intermediate output of the gateway generator 4 through the element OR 2, and then restarted by a selectable pulse passing to the output bus. The same impulse resets shaper 4. Thus, the middle of the next strobe will coincide with the expected arrival time of the next pulse of the sequence. In the case of a pulse skip ig.2), the element 3 is triggered in the middle of the strobe by a signal from the intermediate output of the formator of the bed 4, which in this case forms a complete strobe. If any selectable pulse hits the middle of the strobe, element 3 is triggered by a signal from the output of the OR 2 element, the outputs of which simultaneously receive signals from the output of the pulse selector and from the intermediate output of the driver 4. Each pulse of the gate comes from the output of the driver 4 to the device 6, the conversion factor H of which is equal to the maximum allowable ratio of the number of passes of the selected pulses. The device 6 changes its state on the falling edge of the strobe pulse, provided that there is no signal at its input.

reset, coming from the output of the pulse selector. Otherwise, device 6 is reset. If more than N passes of the selectable pulses have occurred, then at the output of the device 6, the signal of the resetting device 1 and the element 3 is received, thus preparing the pulse selector to start. After that, the first input pulse is passed by the device 1 and through the element OR 2 starts the element 3 of the trigger selector pulses.

Under interference conditions, the reliability of selection by this selector of pulses is higher than that of the prototype, “since in it the sequence pulse interrupts the strobe, therefore, no interference arriving after the sequence pulse can enter the gate. In the prototype, however, the interference received after the pulse of a sequence and entering the gate (which is always fully formed in the prototype) arrives at the output of the selector. This also makes it difficult to make the circuit of the half-cube generator, blocking its start-up at the time of the half-cube formation.

Improving the reliability of selection also contributes to the fact that in this device the counting device is reset only by the pulse of the sequence caught in the strobe, which contributes to reliable fixation of the number of gaps, while in the prototype, the resetting of the counting device occurs on any input pulse outside the strobe, leading to premature dropping

the accumulated result, thus reducing the reliability of fixing the number of skips - pulses.

This pulse selector is simpler than the prototype, since it does not have a half-shaper.

Claims (2)

1. The author's certificate of the USSR (450339, class H 03 K 5/26, 1972. 2. Author's certificate of SSSG 411617, cl. H 03 K 5/26, 1972 (prototype). , -. „,, ,,.,.,.   ,.; (-;   785986 T I Jl b P with d tf F P