RU2005113697A - METHOD FOR MEASURING FREQUENCY AND DEVICE FOR ITS IMPLEMENTATION - Google Patents

Claims (2)

1. The method of measuring frequency, which consists in converting the studied signals of frequency F _x into the studied pulse sequence of the same frequency F _x , in the simultaneous counting of n pulses of the studied sequence of pulses and N counting pulses of frequency F _MF , in determining the frequency value of the studied signals according to the formula

, characterized in that they create a sequence of pulses of a reference frequency F ₀ , from which counting pulses are formed with a frequency F _cf , determined by the requirement for measurement accuracy, and the front of each such pulse is formed on a slice of the corresponding pulse of a reference frequency, and also form the first sequence of pulses with a period following Δt ₁ , determined by the requirement for speed of measurement, simultaneously form a second sequence of pulses with a period of following Δt ₂ , the front of each pulse is This corresponds to the pulse front of the studied pulse sequence, which appeared immediately after the front of the corresponding pulse of the first pulse sequence, after the front of each pulse of the second pulse sequence and the end of the reference frequency pulse acting during this front or the end of the reference frequency pulse arising after the same front at the front of the next reference pulse begin performing frequency with tact Ti, equal to the period T ₀ of the pulse repetition exemplary, tact the desired sequence of operations, moreover, at the first step T1 - the count of n pulses of the studied sequence of pulses and N counting pulses is prohibited, at the second step T2 - the values of the numbers n and N obtained as a result of the previous count of the pulses of the studied sequence of pulses and counting pulses are recorded, at the third step T3 — they generate a signal RDY of readiness for the fixed values of numbers n, N and prepare a new account, ensuring from the next step the count of n pulses of the studied sequence ti and N counting pulses, starting from a value equal to 0, on the fourth step T4 - begin a new simultaneous count of n pulses of the sequence and N counting pulses, and the frequency F _{x of the} studied signals is determined by the readiness signal RDY of fixed values of numbers n and N or at any time during the counting of the new simultaneous pulses n and N candidate sequence count pulses, wherein before determining the frequency F _x to fix the value of N is added number ΔN, equal to the number of periods with edovaniya counting pulses which fit in the time interval determined by the sum of the durations of the three cycles during which the pulse count is a prohibition. 2. A device for measuring frequency, comprising a shaper of the pulse sequence under study, a reference frequency generator, an element NOT, a first counter and register, a second counter and register, and a microprocessor system, the shaper of the pulse sequence being studied is connected to the signal input of the device; the frequency is connected to the input of the element NOT, the data output of the first counter is connected by a bus to the data input of the first register, the data output of the second counter is connected by a bus to the input m of data of the second register, the clock input of which is connected to the clock input of the first register, characterized in that it includes a start pulse shaper, an OR element, a synchronization block, a control unit, a counting pulse shaper and a multiplexer, and the output of the pulse sequence under study is connected to the first the input of the synchronization unit and with the clock input of the first counter, the output of the reference frequency generator is connected to the clock input of the trigger pulse generator and the first input of the control unit Phenomenon, the output of the element is NOT connected to the second input of the control unit and the clock input of the counting pulse shaper, the initial setup bus of the start pulse shaper is connected to the data input of this shaper, and its output is connected to the first input of the OR element, the second input of which is connected to the external start input of the device and the output of the OR element is to the second input of the synchronization unit, the output of which is connected to the third input of the control unit, the first output of the control unit is connected to the enable inputs of the first and second counter s, the second output is with the clock input of the first register, the third output is with the inputs of zeroing the first and second counters and with the interrupt input of the microprocessor system, the fourth output of the control unit is connected to the third input of the synchronization unit, the initial setup bus of the counting pulse generator is connected to the data input of this shaper, and its output is connected to the clock input of the second counter, the data outputs of the first and second registers are connected by buses to the first and second data inputs of the multiplexer, respectively, the third input One of which is connected by a bus to the output address of the microprocessor system, the readout of which is connected to the fourth input of the multiplexer, the data output of the multiplexer is connected via the bus through the microprocessor system to the data output of the device.