JPS6291865A - Waveform shaping circuit for measuring frequency of fundamental wave of distorted wave - Google Patents

Abstract

PURPOSE:To measure a fundamental frequency extending from a low frequency to several kHz, by constituting the titled circuit so that an output signal of an RS-FF is divided by a frequency dividing FF, and thereafter, brought to frequency multiplication. CONSTITUTION:An input signal being a distorted wave is led to comparators A1, A2, and an output of the comparator A1 is led to one input terminal of an RS-FF L1, and an output of the comparator A2 is led to the other input terminal of the FF L1 through an inverter NOT. As a reference signal for a comparison, signals -VP1, +VP2 are inputted to the comparators A1, A2, respectively. Also, the FF L1 is brought to an inversion control each time by the input signal. An output signal of the FF L1 is divided by a frequency dividing FF L2, and also an output signal of the FF L2 is two-multiplied as to its frequency by a frequency multiplying circuit 1, by which a pulse signal of a pulse width being equal to a half period of a fundamental wave of a distorted wave is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a waveform shaping circuit for measuring the fundamental frequency of a distorted wave.

[Prior art and its problems]

Conventional frequency measurement devices could not directly measure the fundamental wave frequency of distorted waves that cross zero for many days within a half period of the fundamental wave. [Object of the Invention] The present invention The object of the present invention is to provide a waveform shaping circuit that enables the measurement of fundamental wave frequencies ranging from low frequencies to several Kflz even in the case of distorted waves as described above.

[Key points of the invention]

The waveform circuit according to the present invention includes two comparators that compare input signals, which are distorted waves whose fundamental wave frequencies are to be measured, with a predetermined level with different polarities, and an output of one of the two comparators. An 88 flip-flop that is set by a signal and reset by the output signal of the other comparator, a frequency dividing flip-flop connected to the rear stage of this l-1,S flip-flop, and a divider flip-flop connected to the rear stage of this division flip-flop. It consists of a frequency multiplier circuit.

〔Example〕

FIG. 1 shows an embodiment of a waveform shaping circuit according to the present invention. The input signals e, which are distorted waves, are respectively input to comparators A1. A2
guided by. The output of the comparator A1 is led to one input terminal of the R, S flip-flop L1. It's dark. As a reference signal for comparison, comparator A1
−VPl is input to the comparator A2, and +”P2 is input to the comparator A2. Therefore, for the input signal e, the signal led from each comparator to the flip-flop L1 is as follows.
The trend is as shown in Figure 2. As a result, the flip-flop L1 is controlled to be inverted each time. flip flop L
The output signal of 1 is frequency-divided by the edge-type flip-flop L2, and the frequency of the output signal of the flip-flop L2 is doubled by the frequency multiplier 1, thereby producing a pulse with a pulse width equal to half the period of the fundamental wave of the distorted wave. A pulse signal is obtained.

〔Effect of the invention〕

According to the present invention, one comparator sets the R, S flip-flop, and the other comparator sets the R, S flip-flop.
The S flip-flop is reset, and the output signal of the R8 flip-flop is divided by the edge type flip-flop and then frequency multiplied, so it is not affected by many zero crosses near the zero level of the distorted wave. Without,
A pulse signal having a frequency equal to the frequency of the distorted wave is obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is an operational waveform diagram. AI, A2...Comparator, Ll...RS flip-flop,

Claims (1)

[Claims] Two comparators each receive an input signal, which is a distorted wave whose fundamental frequency is to be measured, and compare it with a predetermined level with different polarities. A distorted wave consisting of an RS flip-flop that is reset by the output signal of the comparator, a frequency division flip-flop connected to the rear stage of this RS flip-flop, and a frequency multiplier circuit connected to the rear stage of this frequency division flip-flop. Waveform shaping circuit for fundamental wave frequency measurement.