JP2759719B2 - Tone burst signal generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tone burst signal generator used for inspection of audio equipment and the like.

[0002]

2. Description of the Related Art FIG. 3 shows a schematic configuration of a conventional tone burst signal generator. As shown in FIG. 3, the output of the oscillator 21 that oscillates continuously is
It is connected to the input of the limiter 23 . Switch 22
The off-side input is connected to ground. The output of the limiter 23 is connected to the input of the amplifier 24, and the output of the amplifier 24 is connected to the input of the voltage comparator 25. The output of the voltage comparator 25 is connected to the input of the wave counter 26. The wave number counter 26 presets the wave number during the tone burst period by the wave number setting control signal 28 output from the wave number setting unit 27, and outputs an on / off control signal 29 for controlling the switch 22. Switch 22
The signal 30 that has been turned on and output, that is, the tone burst signal, is output from the output terminal 31.

Next, the operation of the tone burst signal generator having the above configuration will be described. The voltage comparator 25 compares the input signal with the ground level, converts the signal into a square wave signal, and outputs the signal. In order to operate normally, a steepness is required near the ground level of the input signal. It is. Therefore, the output signal of the oscillator is limited only to the vicinity of the ground level by the limiter 23, and is amplified by the amplifier 24 to obtain a steepness. First, the wave number in the ON period and the wave number in the OFF period of the tone burst signal are set in the wave number counter 26 by the wave number setting control signal 28, and the wave number counter 26 is set in a state where the wave number can be counted. The wave number counter 26 counts the wave number of the output signal from the voltage comparator 25, and turns off the switch 22 by the on / off control signal 29 when the wave number coincides with the set wave number in the on period.
And simultaneously the side, ready to count the wave number of the off period. By switch 22 is turned off side, the output terminal 31 is short-circuited to the ground. Wave number counter 26
Continuously counts the wave number of the output signal from the voltage comparator 25, and when the wave number coincides with the set wave number in the off period,
When the switch 22 is turned on by the on / off control signal 29, the wave number in the on period can be counted in synchronization with the switch 22. When the switch 22 is turned on , the oscillator 2
1 is output from the output terminal 31 as the output signal 30. As described above, in the above-described conventional tone burst signal generation device, the output of the oscillator 21 becomes the output signal as it is during the on-period while repeating the counting of the wave number during the on-period and the on-period. Generates a tone burst signal that goes to the ground level.

[0004]

However, the conventional tone burst signal generator has an amplifier 24 having an amplification factor (the amplification factor is α) in order to operate the voltage comparator 25 normally. 4B, a delay is caused by the amplification degree α, and an on / off control signal 29 which is an output of the wave number counter 26 is affected to cause a delay corresponding to the delay time, so that the switch 22 is switched as shown in FIG. As shown in FIG. 4C, there is a problem that an unnecessary signal is generated at a switching point of the signal between the ON period and the OFF period as the timing is delayed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a tone burst signal generating apparatus in which the generation of an unnecessary signal at the switching point between the ON period and the OFF period is improved. It is the purpose.

[0006]

In order to achieve the above object, the present invention provides a continuously oscillating oscillator and a steep waveform output.
With ground level by limiter to obtain
A second amplifier for amplifying the near waveform output, and a second amplifier.
Output the wave number by comparing the output of the
Voltage comparator and the on / off period of the tone burst signal.
Wave number setting part for setting wave number, and wave output from voltage comparator
Count the number to match the wave number set in the wave number setting section.
A wave number counter that outputs an on / off control signal when the
The output of the oscillator is turned off by the on / off control signal of the number counter.
Switch that turns off and outputs the tone burst signal.
A tone burst signal generator having
Attenuating the waveform output to the reciprocal of the amplification of the second amplifier
Attenuator and the output of the attenuator are amplified by the amplification of the second amplifier.
And a first amplifier for inputting to the switch unit .

[0007]

According to the present invention, therefore, the output of the oscillator is set to 1
/ Α, and the output of the attenuator is input to the first amplifier which amplifies with the amplification factor α, so that the voltage comparator operates normally without changing the amplitude.
To obtain an output delayed by a time equal to the delay time generated in the second amplifier having the amplification degree α necessary for the amplification. Therefore, since the delay between the on / off control signal and the signal input to the on side of the switch becomes equal, the switching timing of the switch can be matched, and the unnecessary signal at the switching point of the signal between the on period and the off period can be reduced. It is possible to generate a tone burst signal whose generation is suppressed.

[0008]

FIG. 1 is a schematic block diagram of a tone burst signal generator according to an embodiment of the present invention.
In FIG. 1, reference numeral 1 denotes an oscillator that oscillates continuously , and its output is connected to the input of a 1 / α attenuator 2 and a limiter 5 whose reciprocal is a multiple of the amplification factor . The output of the attenuator 2 is input to the first amplifier 3 amplification factor alpha, the output of the first amplifier 3 is connected to the input terminal of the on side of the switch 4. The output of the limiter 5 is connected to the input of the second amplifier 6. The output of the second amplifier 6 is connected to the input of the voltage comparator 7, and outputs the converted square wave signal by comparing the voltage comparator 7, the input signal at the ground level. Further, the output of the voltage comparator 7 is connected to the input of the wave number counter 8, with the wave number counter 8, the tone burst signal set to the wave number setting unit 9 ON period and OFF
By the wave number setting control signal 10 output according to the period ,
The wave number of the tone burst period is preset, and the on / off control signal 11 is output. The ON / OFF control signal 11
The output signal 12 (tone burst signal) is output from the output terminal 13 via the switch 4.

Next, the operation of the above embodiment will be described.
The operations of the limiter 5, the second amplifier 6, the voltage comparator 7, the wave number counter 8, the wave number setting unit 9, and the wave number setting control signal 10 are as follows.
Since the limiter 23, the amplifier 24, the voltage comparator 25, the wave number counter 26, the wave number setting unit 27, and the wave number setting control signal 28 of the conventional example are respectively the same, the description is omitted. The second amplifier 6 necessarily has an amplification degree, which is referred to as α. The attenuator 2 has a function of attenuating its input to 1 / α. The first amplifier 3 has a function of amplifying its input with an amplification factor α. The output of the oscillator 1 is input to the attenuator 2, and the output amplitude of the attenuator 2 is 1 / α of the output amplitude of the oscillator 1. The output of the attenuator 2 is input to the first amplifier 3 and its output amplitude becomes α times the output amplitude of the attenuator 2, that is, equal to the output amplitude of the oscillator 1. Then, although the amplitudes become equal, the first amplifier 3
The delay shown in FIG. However, the delay time is equal to the delay time caused by the amplification degree α of the second amplifier 6 required for the voltage comparator 7 as shown in FIG. That is, the output of the oscillator is delayed by a time equal to the delay of the on / off control signal 11, and is input to the on side of the switch 4, so that the switching timing of the switch 4 can be matched. As described above, according to the above embodiment, the output of the oscillator 1 is input to the attenuator 2 whose input is 1 / α, and the output of the attenuator 2 is input to the first amplifier 3 having the amplification factor α. As a result, an output having a delay time equal to the delay time of the on / off control signal 11 is obtained. As a result, as shown in FIG. 2, it is possible to improve the generation of unnecessary signals at the switching point between the ON period and the OFF period.

[0010]

As described above, according to the present invention, when the amplification degree of the amplifier required for the voltage comparator is α, the output of the oscillator is input to the attenuator which reduces the input to 1 / α, Switch output by inputting the output of the amplifier to an amplifier that multiplies the input by α, and using the delay time in the amplifier having the amplification factor α to obtain a delay time equal to the delay time of the signal for controlling the switch on / off, By adjusting the timing, there is an effect that it is possible to provide a tone burst signal in which generation of an unnecessary signal is suppressed at a switching point of a signal between an ON period and an OFF period.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a tone burst signal generator according to one embodiment of the present invention.

FIG. 2 is a waveform diagram of each part of the tone burst signal generation device according to one embodiment of the present invention.

FIG. 3 is a schematic block diagram of a conventional tone burst signal generator.

FIG. 4 shows waveforms at various parts of a conventional tone burst signal generator.

[Explanation of symbols]

1,21 ... oscillator, 2 ... attenuator, 3 ... first amplifier,
4, 22 switch, 5, 23 limiter, 6 second amplifier, 7, 25 voltage comparator, 8, 26 wave counter, 9, 27 wave number setting unit, 10, 28 wave number setting control signal , 11, 29 ... ON / OFF control signal, 12, 30, ... output signal, 13, 31, ... output terminal, 24 ... amplifier.

Claims (1)

(57) [Claims] An oscillator that continuously oscillates and a steep waveform output
Ground level by the limiter to obtain
A second amplifier for amplifying the waveform output near the
Compare the output of the second amplifier with the ground level
Voltage comparator and tone burst signal on
A wave number setting unit for setting a wave number in an off period;
Count the number of waves output from the vessel and set it in the wave number setting section
Output on / off control signal when the wave number matches
Wave number counter and on / off control signal of the wave number counter
To turn on and off the output of the oscillator
Tone burst signal having a switch for outputting a signal
In the generator, the waveform output of the oscillator is inverted with respect to the amplification degree of the second amplifier.
An attenuator that attenuates several times, and an output of the attenuator,
A first amplifier that amplifies the signal with the gain of the amplifier and inputs the amplified signal to the switch unit
Switching by the on / off control signal
The tone burst signal matched with the
Tone burst signal generating device and outputs.