SU577639A1 - Device for comparing periods of two periodic signals - Google Patents

Description

to the positive fronts of the input pulses.

The initial state of these triggers must be such that the direct output has a logical O state and an inverse logical one. At the same time, these pulses are fed to the inputs of counting triggers 7 and 8 operating in the frequency division mode.

The clock frequency signal arrives at the set trigger inputs for a clear fixation of their states at the time of the pulse pulse clock trigger. From this it follows that in the interval equal to the period 7m-1 / - t of the clock pulse, the counting triggers 7, 8 are triggered by each positive edge of the pulses of the input signals. However, at the time of clock flow, the counting triggers 7 and 8 are reset to their original state if the state of their outputs does not correspond to the required ones.

Triggers 1 and 2 are triggered by the first positive edge of the input signals since the start of the clock neorod. The first positive edges of the square pulses, located in time after the clock frequency pulse, represent the beginning of the first periods of the compared oscillations in the period of the clock signal. The direct output of trigger 1 is associated with the input of an equivalence determination unit 10. Inverse trigger output 2 is connected to another input of this unit. The peculiarity of the operation of the equivalence determination unit 10 is that the output voltage produces positive values if both input signals correspond to logical 1 and negative values if there are two logical signals at the input 0.

The output impulse voltages from the counting triggers 7 and 8 are connected to the first inputs of the triggers 3 and 4, which are triggered by the first positive front of the incoming pulses. The first positive fronts of the pulse sequences represent the ends of the first periods of the original oscillations in each period of the clock signal. Therefore, the state of the triggers 3 and 4 characterizes the temporal position of the ends of the first periods of the input signals in each period of the clock pulses. The direct output of trigger 3 is connected to the first input of the ambiguity determination unit 11, and the inverse output of the trigger 4 is connected to the second input of this unit. The signal at the output of the equivalence determination unit 11 depends on the value of the input signals of the block. Impulse voltage from the output of the block And characterizes the time shift of the ends of the first periods

comparing koleoanii in each period of the clock signal.

The voltages from blocks 10 and 11 of the equivalence determination are supplied to inputs B1–1 of the reader 9. The alternating pulse sequence from its output reflects the difference between the periods of the oscillations being compared, and the total duration (taking into account the sign) of the time shift of the beginning and

the ends of the first periods of the input oscillations in each clock cycle of the signal determines the difference of the period, as well as the difference of frequencies. This signal is fed to the input of the low-pass filter 12, but the nominal output of which is proportional to

the differences of the periods of the input signals, and

the sign of this voltage determines what

of the input frequencies more.

The proposed device for comparison

Two periods of two periodic oscillations make it possible to improve the speed at which information about the frequency difference between the two signals is allocated. The speed is determined by the minimum time required

extracting the idle signal of the mismatch between the input signals and the corresponding moment of the end of the first cycle of extracting the difference of the periods (frequencies) of the original oscillations.

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Claims (2)

1. For Japan’s No. 44-10917, cl. 110D 15, 02.02.69. 2. USSR author's certificate number 406312, cl. H 03 D 13/00, 09.08.71.