SU790168A2 - Device for obtaining difference frequency from two pulse trains - Google Patents

Description

2 second impulses that are connected to the inputs of the element

3 matches connected by its output through a 4-impedance expander to one / y input of trigger 5, the second input of which through differentiating element 6

connected to the input 1 of the device, and the output output of the difference frequency of the device, through the one-shot 7 connected to the same input element 8 match. The second input element 8 is connected to input 2 of the device, and the output is connected to the first, for example, the single input of the sign trigger 9, the second, zero inlet of which through the differentiating

Link 1O is connected to the output of the device. Two separate outputs of flip-flop 9 are used to indicate the sign of the difference in input frequencies.

The voltage index on the time diagrams (Fig. 2) corresponds to the number of the element at the output of which this signal exists. The voltage and at the single output of the trigger of sign 2 is represented as the voltage. The left part of the time diagrams corresponds to the case when the signal frequency at the output 1 of the device is higher than the frequency of the output signal. The right part of the time diagrams corresponds to the opposite frequency ratio.

The device works as follows ...

The signals of the two sequences U (and Uij are fed to the inputs 1 and 2 of the device in the form of pulses with a certain finite duration Ln, which is chosen based on the condition that it is more than half of the maximum possible difference between the periods of the compared pulse sequences.

The signals from inputs 1 and 2 are fed to the coincidence element 3, at the output of which coincidence signals Uj appear, depending on the temporal position of the input pulses in the form of packs consisting of one or several pulses. These pulses are extended in duration using a 4 impedance spreader, in which the one-shot is used to a value slightly longer than the t-n duration of the input pulses, after which U is fed to one of the separate setup inputs of trigger 5. For definiteness, we assume that they are fed to a single input.

The signal from input 1 is also fed to the input of differentiating link 6. Prodi | a) impulse impulses (Uj,)

served on another (zero) trigger setup input. Both inputs of the trigger 5 corresponding to the inclusion of the diodes are set to the mode in which the trigger reacts to write to negative pulses.

In the process of allocating the difference frequency in the absence of coincidence of the input impulses (and and UQ) in time, the trigger is in the zero state under the action of repeated negative impulses from the output of the link 6. When the impulses of the sequence coincide in time, the first pulse of the coincidence signal bursts (Ui, ) after passing through the expander impulse of coincidence (s), the trigger 5 is switched to the opposite state, in which the signal (U) is received at its single output. The trigger is then transferred to the previous zero state performed by the signals U, from the output of the differentiating link, after the end of the bundle of coincidence pulses. B. In the process of action of a burst of coincidence pulses, the trigger does not respond to signals from the output of the differentiating element, since the extended signals of the coincidence pulses overlap them in time.

The moment of the beginning of the coincidence pulse always comes before the negative pulse from the output of the differentiating link, since it is determined by the leading edge of one of the signals of the coinciding pulse, sequences, and the control signal from the output of the differentiating link - by the falling edge of the sequence signal input to input 1. The end point the coincidence impulse comes after the negative impulse from the differentiating link due to its expansion.

The output signal of the trigger 5 is fed to the differentiating link Yu, the output of which has short pulses (), next with the difference frequency, the negative impulses coincide in time with the end of the ultrasonic signals and the negative pulses go to one of the inputs (for example, zero) of the sign trigger 9, which, under the action of these pulses, translates to the zero position.

Claims (2)

To indicate the sign of the difference, the output signal of the trigger 5 (Ug) is also fed to the one-shot 7, which, under the action of the falling edge of the pulse Ijg, generates a short single pulse (U-). The duration of this pulse is larger than the maximum difference between the periods of the compared pulse sequences 4 and UQ. Such a choice of the duration of a single-pulse single pulse pulse ensures that, during its existence time, the next pulse of the sequence begins to arrive at input 2 (if the frequency of the pulses at input 2 is lower than the frequency of the pulses at input 1). As a result of the supply of such signals to the inputs of the clutch element 8, the output of the latter produces a signal (VJg), the leading edge of which coincides with the leading edge of the pulse at the input 2. If the frequency of the pulses at input 2 is greater than the frequency of the pulses at input 1, then the signals arriving at the input of element 8 do not coincide. The signal UQ from the output of element 8 coincides with the second 9-pin trigger input of sign 9, wherein (figure 2 if the frequency of the signal at input 2 of the device is greater than the frequency of the signal at input 1, then there are no pulses at the output of element 8 of coincidence 1, arrive only at the zero input of the sign trigger, which is all the time in the zero position. If the frequency of the signal at input 2 is less than the frequency of the signal at input 1 of the device, two tamynbCOB sequences (Ua and LI, (Q)) the result of which, having transferred to the pinch In this case, the trigger 9 immediately perceives the signal yjn, which leads it to the bopy part of the difference frequency period in a single state. The outputs of the sign trigger can be connected to the corresponding display devices or the difference sign. Invention YcTpoifcTBO to get a difference frequency from two and pulse sequences according to auth. St. No. 301855, characterized in that, in order to expand the functionality, a differentiating link, a one-shot, coincidence element, and a trigger, whose outputs with Connected to the sign indication tires, the first input through the differentiating link, and the second input through the serially connected one-shot and the matching element to the device output, the second input of the matching element to the second input of the device. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 301855, cl. H 03 K 19 / 2O, 1969.  - S 7 ig.1 NJ i J. 1 -SJi% 1 | 4 4i 44J; four d c: :} 4J . M .. i3 ia cvj : : : 5V 3