SU871151A2 - Amplitude differential zero element - Google Patents

Description

one

The invention relates to the field of automation and can be used in devices for tolerance control of parameters of complex quantities, bridges and alternators of alternating current.

According to the main author. St. 341003 known null-organ, serially connected cathode follower, rectifier, filter and serially connected second cathode repeater, second rectifier, attenuator and comparison circuit, a serial string of the amplifier-limiter and time delay block, the output of which is connected to the second input of the circuit comparison, and the output of the filter through a voltage divider is connected to the third input of the comparison circuit 1.

The disadvantage of a null organ is that it has a limited scope.

The purpose of the invention is to expand the scope of the null organ.

 This goal is achieved by introducing a counter into the known amplitude-differential zero-body, the first input of which is connected to the output of the comparison unit and to the second input

voltage divider, and the second input to the output of the time delay unit.

FIG. 1 shows a functional diagram of the zero-body; Fig. 2 is a timing diagram explaining the operation of the null organ.

The zero-body contains the first and second matching blocks (cathode repeaters) 1 and 2, the first and second

10 rectifiers 3 and 4, limiting amplifier 5, filter b, attenuator 7, time delay block 8, voltage divider 9, comparison block (comparison circuit) 10 and counter 11.

15

The zero-body works as follows.

The voltages U to (}, i ((through matching blocks 1 and 2 and rectifiers 3 and 4 are fed to filter 6 and 20 attenuator 7, respectively. From the output of filter 6, the signal of a constant level goes through a divider voltage of 9 the first (signal) input of the comparator unit 10. From the output 25 of the attenuator 7, a pulsating signal attenuated by an amount equal to the losses in the filter 6 is fed to the second signal input of the comparator unit 10. The signal from the output of the matching unit 30 3 through the limiting amplifier 5 and

The time delay unit 8 is supplied simultaneously to the control input of the comparison unit 10 and the second (control) input of the counter 11.

The time delay unit 8 permits (opens the inputs of the comparison unit 10) a comparison of the signals from the output of the attenuator 7 and the signal from the output of the Voltage divider 9 from the time point b a, i.e. the moment of transition of the harmonic signal Ua through zero (level from minus to plus during; Interval of time iit to the moment -t. The time interval -fc is less than 1/4 of the period of the harmonic signal Urj. f and its minimum value is limited by the accuracy requirements. From time -fc Яо moment of equality of signals with voltage divider 9 and attenuator 7 transmission coefficient of serially connected filter b and voltage divider 9 is equal to K (and, where KE iviuJut, W is the circular frequency of the signals and, and h is the number of discrete signal levels and from the output of the voltage divider 9 when this signal changes from O to UD ДЬ / and the i-th level differs from (-iD-ro level by an amount depending on the amplitude of the harmonic signal U (and paBjiyroU К .. | and. At the moment of equality of the signals from the outputs of the attenuator 7 and voltage divider 9, a short pulse from the output of the comparator unit 10 is fed simultaneously to the input of counter 11 and the second (control) input of voltage divider 9, the transmission coefficient of which instantaneously increases by K (and and remains constant until the next pulse from the output of the comparison block 10, i.e. until the closest equality of these signals. This process of changing the signal level from the output of the voltage divider

9 and comparing it with the signal from the output of the attenuator 7 occurs during the time interval At, and the reading of the counter 11 hi at the time instant Lz is equal to the ratio of amplitudes of harmonic signals Ol and multiplied by the number VI, i.e.

ABOUT

- J2L.V ..

hiI and

ABOUT

wi

where yyu, and (intt amplitudes of the harmonic signals U and and «1...

If the reading m of counter 11 is greater than the number VI, then U, BV i | npa3 and 5 vice versa.

The use of the invention allows to obtain a code proportional to the ratio of the amplitudes of the compared harmonic signals, which will make it possible to use a null organ in high-speed bridges, compensators, as well as in systems of automated control and management of technological processes. In this way, the scope of the nullgawa will expand.

Claims (1)

1. USSR author's certificate 341003, cl. G 05 B 1/01, 1971 (prototype). fff