JPH0241952Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a frequency signal generation circuit for intermittently generating a signal whose frequency changes stepwise at the same frequency multiple times.

A sensor mainly composed of, for example, a crystal oscillator that resonates at a specific frequency is attached to the object to be measured, and the physical phenomenon of the object to be measured is determined from the resonant frequency of the sensor.
For example, a wireless telemeter system that non-contactly measures temperature, strain, etc. is configured to send an excitation signal from a fixed station to the sensor, and then receive a response signal, such as an echo signal from the sensor, at the rotating station. Therefore, the fixed station must be configured to alternately switch between a transmission mode in which it sends out an excitation signal and a reception mode in which it receives an echo signal, and the excitation signal must be generated intermittently.
Furthermore, in order to find the resonant frequency of the sensor, it is necessary to scan a predicted frequency range by changing the frequency of the excitation signal stepwise.

Furthermore, for example, if the object to be measured is something that is constantly moving or in motion, such as a rotating body, an excitation signal is transmitted when a mobile station (a station equipped with a sensor and attached to a rotating body) and a fixed station approach each other. In order to achieve this, it becomes necessary to generate an excitation signal of the same frequency multiple times and change the frequency stepwise.

The object of the present invention is to provide a frequency signal generation circuit used in the wireless telemeter system as described above.

For this purpose, in the present invention, the repetition period of the pulse output from the pulse signal generator is divided by N times and then counted, and the counting output is converted from digital to analog to generate an analog signal with a voltage corresponding to the counting output. This analog signal is then voltage-frequency converted to obtain a signal whose frequency changes stepwise, and this signal is turned on/off by a pulse signal from a pulse signal generator.
The OFF control is performed to obtain a frequency signal whose frequency changes stepwise and which occurs intermittently a plurality of times within the same frequency. In other words, the period of the rectangular signal obtained by dividing the frequency by the frequency division ratio N is N times the period of the original pulse signal, and the frequency obtained based on this rectangular signal changes stepwise. The duration time at each frequency of the signal is the period time of the rectangular signal, so if this is controlled on/off using the leading and trailing edges of the original pulse signal,
The number of intermittent times within the same frequency of the intermittent frequency signal obtained by this is N times, which is equal to the frequency division ratio N.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a time chart explaining its operation.

Each part of the embodiment will be explained with reference to FIG.

1 is a pulse signal generator, and the duration and repetition period of the frequency signal to be finally obtained are determined by the pulse width and repetition period of the pulse signal output from this pulse signal generator 1. In addition, in the embodiment, this pulse signal generator 1
The clock oscillator (CLOCK.OSC) that generates the clock pulse that serves as the operating time reference for the entire system using the intermittent frequency signal generation circuit is used as is. (Hereinafter, it will be explained as a clock oscillator.) 2 is a frequency divider (DIVIDER) with a frequency division ratio N, which outputs a signal (rectangular signal) with a period N times the repetition period of the clock pulse output from clock oscillator 1. do. The number of times the frequency signal to be finally obtained is repeatedly generated within the same frequency is determined by the frequency divider 2.
It is determined by the frequency division ratio N of , and becomes N times. Also,
By making this frequency division ratio N variable, for example, by setting a dial, the number of repetitions of the frequency signal within the same frequency can be arbitrarily set.

3 is a counter (COUNT) which counts the output signal from the frequency divider 2 and outputs a count value for each count.
The maximum count value of this counter 3 is M, and when it counts up to M, the count value returns to the initial value "0", and the count up to M is repeated thereafter. The number of frequency changes of the frequency signal to be finally obtained is determined by the maximum count value M of this counter 3, and is M times. Also,
By making this maximum count value M variable, for example, by setting a dial, the number of frequency changes, that is, the range of frequency changes, can be arbitrarily set.
In this embodiment, this counter 3 is a binary counter (BIN.
COUNT.) is used.

4 is a digital-to-analog converter (D/A
CONV.Hereafter referred to as a D/A converter. ), counter 3
A voltage signal is output by converting the output (digital value) for each count into a corresponding voltage value (analog value).

Reference numeral 5 denotes a voltage-frequency converter (V/F CONV. hereinafter referred to as a V/F converter), which outputs a frequency signal obtained by converting the voltage signal output from the D/A converter 4 into a corresponding frequency.

The frequency of the frequency signal to be finally obtained and its range of change are the conversion ratio (the amount of change in the analog value for a unit change in the digital value) P of the D/A converter 4, and the above-mentioned The conversion ratio (the amount of change in frequency with respect to a unit change in voltage value) of the V/F converter 5 is determined by Q, and the conversion ratio P or Q is determined by, for example, a dial setting. Therefore, if it is made variable, the frequency of the frequency signal and its range of change can be set arbitrarily.

6 is a switch circuit (SWITCH) which controls on/off the frequency signal output from the V/F converter 5 with the clock pulse output from the clock oscillator 1, and generates the final frequency signal, that is, intermittently generates the frequency signal output from the clock oscillator 1. And outputs an intermittent frequency signal whose frequency changes stepwise every time it occurs multiple times.

Next, the operation of the embodiment will be explained with reference to FIG.

As shown in FIG. 2A, the clock oscillator 1 always outputs a pulse signal of a constant width to a point A at a constant repetition period. This pulse signal is input to a frequency divider 2 and divided by a frequency division ratio N. In the example shown in Fig. 2, the frequency division ratio N is set to 6, and the frequency divider 2 divides the frequency of the above pulse signal by 6, and as shown in Fig. 2B, three pulse signals are input. The polarity is reversed every time (the polarity is reversed at every leading edge of the fourth pulse)
Since an output signal is output, a rectangular signal whose period is six times that of the pulse signal at point A is always sent to point B, as shown in FIG. 2B.

The signal output at point B is input to the counter 3 and counted. In the embodiment, the maximum value M of this counter 3 is set to 5 counts (“0” is also considered 1 count), and the counter 3, which is a binary counter, is set to B
Every time a point signal is input, its output is changed from “0000” to “0100” (from “0” to “4” in decimal notation,
Note that the counter 3 is a 4-bit counter. ), and when a signal corresponding to "0101" is outputted to point B, the counter 3 is cleared by the signal and its output returns to "0000", and the above operation is repeated thereafter. The result counted by the counter 3 as described above is output to point C as shown in FIG. 2C.

The counting result outputted to point C by the counter 3 is a digital value, and the signal of this digital value is D/
The A converter 4 converts the voltage into analog voltages, and outputs voltage signals of voltages E ₁ to E ₅ at point D as shown in FIG. 2D. In addition, the voltage change (increase) ΔE every time the count value increases by one count is constant,
If the voltage when the count value is "0000" is "E ₁ ", then counting from "0000" and counting time (n
≦M. ) voltage E _o is “E ₁ +(n-1)ΔE”.

The voltage signal outputted to point D as described above is then input to the V/F converter 5 and converted into a frequency signal, and as shown in FIG. 2E, the frequency changes every time the voltage signal changes. A frequency signal is output to point E. In the example shown in FIG. 2, this frequency signal becomes a signal whose frequency changes every time corresponding to 6 (=N) cycles of the pulse signal because the frequency division ratio N of the frequency divider 2 is 6. . Also, the frequency change (increase) Δ for each step is constant, and when the voltage value is “E ₁ ” (count value is “0000”), the frequency is “ ₁ ” (count value is “0000”). frequency is “ ₁ ”
If so, the frequency _o of the signal at the n-th step counting from "E ₁ " (where n≦M) is " ₁ + (n-1) Δ".

The frequency signal output to point E and the pulse signal output to point A become the controlled input and control input of the switch circuit 6, respectively, and the frequency signal output to point E corresponds to the pulse signal. The signal is output to point F through the switch circuit 6, which is turned on at the leading edge (rising) and turned off at the trailing edge (falling). As a result, at point F, as shown in FIG. A frequency signal that occurs at
In addition, in FIG. 2, the waveforms of E and F are shown as a model by their envelopes for simplicity.

Incidentally, a frequency signal may be outputted to point F between the trailing edge (falling edge) and leading edge (rising edge) of the pulse signal input to the control input of the switch circuit 6. This is possible by changing the design.

As explained above in detail, the present invention can generate a signal of the same frequency multiple times intermittently, and can obtain a circuit that repeats this operation by changing the frequency stepwise with a simple configuration. This is extremely effective for devices that need to scan intermittently and multiple times at the same frequency.

Although the present invention was developed in response to the request for a rotating body non-contact wireless telemeter system as described above, it is possible that the present invention can be implemented in all devices that require a signal of the form shown in Fig. 2F. It is clear that differences in the implementation equipment do not change the gist of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a time chart explaining its operation. Explanation of symbols, 1... Pulse signal generator (clock oscillator), 2... Frequency divider, 3... Counter, 4...
...D/A (digital-analog) converters 4, 5...
...V/F (voltage-frequency) converter, 6...switch circuit.

Claims (1)

[Claims for Utility Model Registration] 1. The operation of intermittently generating a signal of the same frequency N times (N>1) is performed by changing the frequency stepwise M times (M>
1) An intermittent frequency signal generation circuit that repeats while changing a pulse signal generator, a frequency divider that multiplies the pulse repetition period of the pulse signal generator by N times, and counts the output signal from the frequency divider. A counter with a maximum count value M, a digital-analog converter with a conversion ratio P that converts the count output of the counter for each count into a voltage signal, and a voltage signal output from the digital-analog converter. A voltage-frequency converter with a conversion ratio Q that converts into a frequency signal, and on/off control of the leading and trailing edges of the pulse signal from the pulse signal generator, and the voltage -
An intermittent frequency signal generation circuit consisting of a switch circuit that intermittently outputs a frequency signal from a frequency converter. 2. The intermittent frequency signal generation circuit according to claim 1, in which the frequency division ratio N of the frequency divider can be variably set. 3. The intermittent frequency signal generation circuit according to claim 1, in which the maximum count value M of the counter can be variably set. 4. The intermittent frequency signal generation circuit according to claim 1, in which the conversion ratio P of the digital-to-analog converter can be variably set. 5. The intermittent frequency signal generation circuit according to claim 1, in which the conversion ratio Q of the voltage-frequency converter can be variably set.