SU976396A1

SU976396A1 - Digital frequency meter

Info

Publication number: SU976396A1
Application number: SU813277568A
Authority: SU
Inventors: Виталий Федорович Тихомиров
Original assignee: Предприятие П/Я Г-4590
Priority date: 1981-04-20
Filing date: 1981-04-20
Publication date: 1982-11-23

Description

(54) ЦИФРОВОЙ ЧАСТОТОМЕР(54) DIGITAL FREQUENCY

Изобретение относитс к электроизмерению и может быть использовано в цифровых измерител х частоты.This invention relates to electrical measurement and can be used in digital frequency meters.

Известен цифровой частотомер,состо щий из псрследовательно соединенных генератора опорной частоты, формировател импульсов опорной частоты, делител , триггера со счетным входом , управл ющего ключом, второй вход которого соединен с формирователем импульсов измер емой, частоты, и счетчика импульсов 1.A digital frequency meter is known that consists of a reference frequency generator, a reference frequency driver, a divider, a trigger with a counting input, a control key, the second input of which is connected to a measured frequency generator, and a pulse counter 1.

Частотомер имеет неоднозначность отсчета, обус 1овленную ошибкой квантовани и некогерентностью измер емой и.опорной частот.The frequency meter has a counting ambiguity caused by a quantization error and incoherence of the measured and reference frequencies.

Наиболее близким по технической сущности к изобретению вл етс цифровой частотомер, подсчитывак ций число периодов измер емой частоты за известный промежуток времени и содержащий последовательно соединенные фо{7мирователь импульсов измер емой частоты, ключ, счетчик импульсов, цифровой индикатор и последовательно соединенные генератор опорной частоты и делитель опорной частоты, вы .ход которого соединен с вторым входом ключа С 23 .The closest in technical essence to the invention is a digital frequency meter, counting the number of periods of the measured frequency for a known period of time and containing series-connected photo {7wirers of measured frequency pulses, key, pulse counter, digital indicator and series-connected reference frequency generator and divider the reference frequency, which is connected to the second input of the C 23 key.

Однако известный частотомер не обеспечивает однозначность отсчета частоты.However, the known frequency meter does not provide an unambiguous reference frequency.

Цель изобретени - повышение точности отсчета измер емой частоты.The purpose of the invention is to improve the accuracy of the reference of the measured frequency.

.Поставленна цель достигаетс тем, что в цифровой частотомер, содержащий генератор опорной частоты, делитель частоты, цифровой И-ндика10 тор, счетчик импульсов, ключ, формирователь импульсов измер емой частоты , вход которого соединен с входной шиной устройства, а выход формировател импульсов измер емой частоты The goal is achieved by the fact that a digital frequency meter containing a reference frequency generator, a frequency divider, a digital I-indicator, a pulse counter, a key, a pulse frequency generator of the measured frequency, the input of which is connected to the input bus of the device, and the output of the pulse shaper measured frequencies

15 подключен к входу ключа, выход которого соединен со счетчиком импульсов, выход которого подключен к входу цифрового индикатора, выход генератора опорной частоты соединен с входом де20 лител частоты, введен D-триггер, С-вход которого соединен с выходом формировател импульсов измер емой частоты, В -вход B -триггера подключен к выходу делител частоты, а выход D-триггера соединен с управл ющим входом ,15 is connected to the key input, the output of which is connected to a pulse counter, the output of which is connected to the digital indicator input, the output of the reference frequency generator is connected to the input of a frequency converter, a D-trigger is inserted, the C input of which is connected to the output of the measured frequency pulse former, Input B of the trigger is connected to the output of the frequency divider, and the output of the D flip-flop is connected to a control input,

Claims

FIG. 1 shows a block diagram of a frequency meter; FIG. 2 - time charts of the reference frequency. The frequency meter contains 1 reference frequency generator, 2 frequency divider, shaper of 3 measured frequency pulses, D-trigger 4, key 5, impulse counter 6, digital indicator 7. The frequency meter works as follows. The frequency divider 2 divides the frequency of the generator 1 to a value that is determined by the selected counting time T, From the output of the divider, a pulse of duration TO arrives at the input of the D-flip-flop 4.. The oscillations of the voltage of the measured frequency are transformed by the shaper 3 into a sequence of pulses that arrive at the input of the key 5 and at the C input of the D-trigger 4. As follows from the principle of operation of a two-step, synchronized front .D-trigger, in any state of the Match, the state change Neither T) causes a change in the exit state. Only at the moment of the transition of the C-input potential from state 1 to state O will the output state change. Moreover, the output state will correspond to the D-input state at the moment of transition of the state from 1 and O. The signal from the D-Trigger 4 output goes to the control input of the key 5. In the output 1 state, the key 5 is open and transmits pulses frequencies. The number of pulses passed through the public key 5 is read by a counter of 6 pulses. The counting results are sent to a digital indicator 7. The time diagrams (Fig. 2 show two extreme and intermediate positions of the measured frequency pulses relative to the counting time pulse H,, Due to the fact that the opening and closing of the key are synchronized by the measured frequency pulses, the input of the pulse counter always passes an integer number of pulses of the same duration. The maximum deviation of the counter reading from the true value lies within. When the frequency changes within the specified error, the reading The tactile sensor remains unchanged and equals the average value. Formula of the Invention A digital frequency meter comprising a frequency generator, a frequency divider, a digital indicator, a pulse counter, a key, a measured frequency pulse generator, the input of which is connected to the input bus of the device, and a pulse frequency generator output of the measured frequency connected to the key input, the output of which is connected to a pulse counter, the output of which is connected to the digital indicator input, the output of the reference frequency generator is often connected to the input of the divider You are characterized in that, in order to increase the accuracy of the reference of the measured frequency, a 1 -thrigger is inputted, the C input of which is connected to the output of the pulse generator measuring the frequency of the frequency, the D input of the Dtrigger connected to the output of the frequency divider, and the output T) The trigger is connected to the control input of the key. Sources of information taken into account in the examination 1, Ermolov RS, Digital frequency meters. L., Energie, 1973, p. 6

2.Ornatsky P.P. Automatic measurements and instruments. Kiev, Vishcha School, 1980, p., 370-374 / prototype).