JP2743533B2 - Sensitivity inspection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensitivity inspection apparatus, and more particularly to a sensitivity inspection apparatus that detects the sensitivity of a pager receiver by sound.

[Conventional technology]

A conventional sensitivity inspection apparatus includes a shield box, a microphone installed in the shield box, an amplifier connected to an output of the microphone, a bandpass filter connected to an output of the amplifier, and a bandpass filter. The circuit includes a comparator connected to the output, a latch circuit connected to the output of the comparator, and a control unit connected to the output of the latch circuit. Next, a conventional sensitivity inspection apparatus will be described in detail with reference to the drawings.

FIG. 4 is a configuration diagram showing an example of a conventional sensitivity inspection device. The sensitivity inspection device shown in FIG.
And a pager receiver 19 installed in the shield box 13 and a microphone 14 installed in the shield box 13
And the amplifier 15 connected to the output of the microphone 14, and the amplifier 15
And a comparator 17 connected to the output of the bandpass filter 16
And a latch circuit 18 having a trigger input terminal connected to the output of the comparator 17, and a control unit 20 connected to the output of the latch circuit 18.

Next, the operation, operation, and the like of the conventional example shown in the drawing will be described step by step. Microphone when pager receiver 19 sounds
14 converts the sound wave into an electric signal m and outputs it to the amplifier 15. The amplifier 15 outputs the electric signal n obtained by amplifying the electric signal m to the band-pass filter 16. Band pass filter
A comparator 17 compares an electric signal o, which is a component of the electric signal n and passes only the sound wave frequency of the pager receiver 19 to the comparator 17.
Output to A comparator 17 compares the electric signal o with a threshold level and outputs a square wave electric signal p to a latch circuit 18.
Output to The latch circuit 18 performs a latch operation based on the waveform edge of the electric signal p and outputs an electric signal q to the control unit 20. The control unit 20 detects the sound of the pager receiver 19 based on the electric signal q.

[Problems to be solved by the invention]

In the conventional sensitivity inspection apparatus described above, since the microphone 14 is fixed to the shield box 18, when shock and vibration are applied to the shield box 13 during the inspection, the microphone 14 is fixed to the microphone 14.
Is converted into an electric signal a ', and the control unit 20 cannot distinguish it from the sound of the pager receiver, which may cause a false detection.

[Means for solving the problem]

The sensitivity inspection apparatus of the present invention includes a shield box that blocks an external electric field, a pager receiver installed in the shield box, and a sound wave in the shield box that is installed in the shield box and converts it into an electric signal. A microphone to be connected, an amplifier connected to the output of the microphone to amplify the output signal of the microphone, and connected to the output of the amplifier to output only the sound frequency component of the sound of the pager receiver from the output signal of the amplifier. A band-pass filter to be passed, a comparator connected to an output of the band-pass filter, for comparing an output signal of the band-pass filter with a threshold level to digitize, and an output signal of the comparator connected to an output of the comparator One cycle of the output signal waveform of the comparator by the waveform edge of A mono-multivibrator that outputs a pulse output having the above pulse width, and counts the number of pulses of the output of the comparator while the output of the monomultivibrator is connected to the output of the comparator and the output of the monomultivibrator. A counter that is connected to the output of the counter, a magnitude comparator that compares the output of the counter with a set value and enables the output when the output of the counter becomes larger than a set value, and a magnitude comparator that is connected to an output of the magnitude comparator. A latch circuit that performs a latch operation when the output of the magnitude comparator is enabled and holds the output enabled; and a latch circuit that is connected to the output of the latch circuit and enables the output of the latch circuit to enable the pager receiver. Configured to include a control unit for detecting a sound.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention. The sensitivity inspection apparatus shown in FIG.
And a pager receiver 7 installed in the shield box 1 and a microphone 2 installed in the shield box 1
And an amplifier 3 connected to the output of the microphone 2, and an amplifier 3
And a comparator 5 connected to the output of the band-pass filter 4
And a monomultivibrator 12 having a trigger input terminal connected to the output of the comparator 5, and a monomultivibrator 12 having a count input terminal connected to the output of the comparator 5.
A counter 8 having a clear input terminal connected to 12 outputs,
A magnitude comparator 10 having a comparison value input terminal connected to the count output of the counter 8, a reference value designating circuit 11 connected to a reference value input terminal of the magnitude comparator 10, and a comparison result greater output terminal of the magnitude comparator 10 being triggered. A latch circuit 6 having an input terminal connected thereto, and a control unit 9 connected to a latch output of the latch circuit 6
It is comprised including. Next, the operation, operation, and the like of the configuration and the like shown in the drawing will be sequentially described. When the pager receiver 7 sounds, the microphone 2 converts the sound wave into an electric signal a and outputs the electric signal a to the amplifier 3. The amplifier 3 outputs an electric signal b obtained by amplifying the electric signal a to the band-pass filter 4. The band pass filter 4 outputs to the comparator 5 an electric signal c which has passed only the sound wave frequency of the pager receiver 7 among the components of the electric signal b. The comparator 5 compares the electric signal c with the threshold level and outputs a square wave electric signal d to the count input terminal of the counter 8 and the trigger input terminal of the mono multivibrator 12. The mono-multivibrator 12 outputs to the clear input terminal of the counter 8 a retriggerable pulse electrical signal f longer than one cycle in the sound frequency of the pager receiver 7 at the waveform edge of the signal input to the trigger input terminal. The counter 8 counts the number of pulses of the electric signal d input to the count input terminal while the electric signal f input to the clear input terminal is disabled, and outputs a count output signal g to the comparison value input terminal of the magnitude comparator 10. I do. The magnitude comparator 10 compares the reference value signal i input from the reference value designating circuit 11 connected to the reference value input terminal with the count output signal g, and determines whether the count output signal g is equal to the reference value signal i.
When the value becomes larger than the comparison result, the comparison result becomes larger, and the output signal h is output to the latch circuit 6. The latch circuit 6 performs a latch operation in accordance with the waveform edge of the output signal h which is greater than the comparison result, and outputs an electric signal e to the control unit 9. The control unit 9 detects the sound of the pager receiver 7 based on the electric signal e.

FIG. 2 shows, as a waveform j, an example of an electric signal c when an external impact is applied to the shield box.
An example of the electric signal f, which is an output of the mono-multivibrator 12 and is generated as a result, is shown as a waveform. In the sound detection in this case, the electric signal c has the waveform j only at the moment when the impact is applied.
And the number t of pulses of the electric signal c is smaller than that at the time of sounding of the pager receiver 7. If the reference value signal i of the reference value designating circuit 11 is set to be larger than the number of pulses k at the time of sound detection when an external shock is applied to the shield box, the waveform k will be interrupted when the pulse of the waveform j is interrupted. It is enabled and the counter 8 is cleared. Even when shocks and vibrations are continuously applied to the shield box, the counter 8 is cleared between the shocks, and the count output is cleared. Therefore, only a value smaller than the reference value signal i is input to the comparison value input of the magnitude comparator 10, and the comparison result greater output signal h remains disabled, so that the electric signal e output from the latch circuit 6 is disabled. And the control unit 9 does not recognize the erroneous detection. FIG. 3 shows a waveform r as an example of the electric signal c when the sound of the pager receiver 7 is input to the microphone 2;
Mono-multi vibrator 12 generated by electric signal c
A waveform s is shown as an example of an electric signal f which is an output of the magnitude comparator 10, and a waveform l is shown as an example of a comparison result greater output signal h which is an output of the magnitude comparator 10. When the count output signal g from the counter 8 input to the comparison value input terminal of the magnitude comparator 10 becomes larger than the reference signal i, the comparison result becomes larger and the output signal h is output to the controller 9. Detect the sound of.

〔The invention's effect〕

The sensitivity testing apparatus of the present invention counts the number of pulses of a sound caught by a microphone, thereby separating a sound caused by shock and vibration from a pager receiver and performing a pager receiver sensitivity test with high hardness. There is an effect that can be.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a signal waveform diagram at the time of sounding due to shock and vibration in the embodiment,
FIG. 3 is a signal waveform diagram when a pager receiver sounds in the embodiment, and FIG. 4 is a configuration diagram showing a conventional example. 1,13 …… Shield box, 2,14 …… Microphone, 3,15 ……
Amplifier, 4,16… Band pass filter, 5,17… Comparator, 6,18… Latch circuit, 7,19… Pager receiver, 8… Counter, 9,20… Control unit, 10… ... magnitude comparator, 11 ... reference value designating circuit, 12 ...
Mono multivibrator, a, m ... microphone output signal,
b, n ... amplifier output signal, c, o ... bandpass filter output signal, d, p ... comparator output signal, e, q ...
... output signal of latch circuit, f ... output signal of band-pass filter, g ... output signal of counter, h ... output signal of magnitude comparator, i ... reference value signal of magnitude comparator, j, r ... band An example of the output signal waveform of the pass filter, k, s... An example of the output signal waveform of the mono multivibrator, l... An example of the output signal waveform greater than the comparison result of the magnitude comparator, 5
...... The number of pulses of the output signal of the band pass filter.

Claims (1)

(57) [Claims] 1. A shield box for interrupting an external electric field, a pager receiver installed in the shield box, and a microphone installed in the shield box for converting sound waves in the shield box into electric signals. ,
An amplifier connected to the output of the microphone and amplifying the output signal of the microphone; and a bandpass connected to the output of the amplifier and passing only the sound wave frequency component of the pager receiver in the output signal of the amplifier. Filters and
A comparator connected to the output of the band-pass filter and comparing the output signal of the band-pass filter with a threshold level to digitize the signal; and a comparator connected to the output of the comparator and having a waveform edge of the output signal of the comparator to generate a signal of the comparator. A mono-multivibrator that outputs a pulse output having a pulse width of one cycle or more of an output signal waveform; and A counter for counting the number of output pulses,
A magnitude comparator connected to the output of the counter, for comparing the output of the counter with a set value, and enabling the output when the output of the counter becomes larger than the set value; and a magnitude comparator connected to the output of the magnitude comparator. A latch circuit that performs a latching operation when the output of the pager is enabled to hold the output enabled, and is connected to the output of the latch circuit to enable the output of the latch circuit to detect the sound of the pager receiver. A sensitivity inspection device comprising a control unit.