Device for amplitude adjustment and rectification made with MOS technology
First Claim
1. An amplitude adjustment device which adjusts an amplitude of an input signal to produce an output signal, comprising:
- pulse-width modulation means for effecting pulse-width modulation on the input signal to produce a pulse-width modulated signal;
demodulation means for demodulating the pulse-width modulated signal to produce the output signal;
amplitude detection means for detecting a lower amplitude peak and an upper amplitude peak of said output signal; and
control means for controlling a modulation factor of the pulse-width modulation based on a detection result of the amplitude detection means, wherein a period of said pulse-width modulated output signal is controlled based on a level therebetween said lower amplitude peak and an upper amplitude peak of said output signal.
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Abstract
An amplitude adjustment device such as an amplitude compression device and amplitude expansion device is basically configured by a PWM modulator, a demodulator and an amplitude detector. Herein, the PWM modulator effects pulse-width modulation on an input signal to produce a pulse-width modulated signal, which is demodulated by the demodulator to produce an output signal. In addition, the amplitude detector detects an amplitude of a demodulated signal or an amplitude of the input signal to produce a control signal. A modulation factor of the pulse-width modulation is adjusted based on the control signal. In the case of the amplitude compression device, an input/output gain is changed inversely proportional to the amplitude of the input signal or amplitude of the output signal. Thus, it is possible to compress a dynamic range with respect to input/output characteristics. A full-wave rectifier, applicable to the amplitude adjustment device, is mainly configured by an inversion amplifier, an amplifier and an output section. Herein, the inversion amplifier amplifies an input signal with a gain of “−1”, while the amplifier amplifies it with a gain of “1”. Outputs of the amplifiers differ from each other in phases by 180°. The output section produces a full-wave rectified signal based on the outputs of the amplifiers. Incidentally, all of the amplifiers and output section are configured using field-effect transistors without using diodes being externally connected. Hence, it is possible to manufacture the full-wave rectifier in a form of an IC in accordance with the MOS process with ease.
17 Citations
18 Claims
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1. An amplitude adjustment device which adjusts an amplitude of an input signal to produce an output signal, comprising:
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pulse-width modulation means for effecting pulse-width modulation on the input signal to produce a pulse-width modulated signal;
demodulation means for demodulating the pulse-width modulated signal to produce the output signal;
amplitude detection means for detecting a lower amplitude peak and an upper amplitude peak of said output signal; and
control means for controlling a modulation factor of the pulse-width modulation based on a detection result of the amplitude detection means, wherein a period of said pulse-width modulated output signal is controlled based on a level therebetween said lower amplitude peak and an upper amplitude peak of said output signal. - View Dependent Claims (2, 3)
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4. An amplitude adjustment device which adjusts an amplitude of an input signal to produce an output signal, comprising:
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pulse-width modulation means for effecting pulse-width modulation on the input signal to produce a pulse-width modulated signal;
demodulation means for demodulating the pulse-width modulated signal to produce the output signal;
amplitude detection means for detecting a lower amplitude peak and an upper amplitude peak of said input signal; and
control means for controlling a modulation factor of the pulse-width modulation based on a detection result of the amplitude detection means, wherein a period of said pulse-width modulated input signal is controlled based on a level therebetween said lower amplitude peak and said upper amplitude peak of said input signal. - View Dependent Claims (5, 6)
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7. An amplitude compression device comprising:
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pulse-width modulation means for effecting pulse-width modulation on an input signal to produce a pulse-width modulated signal;
demodulation means for demodulating the pulse-width modulated signal to produce an output signal;
amplitude detection means for detecting a lower amplitude peak and an upper amplitude peak of said output signal; and
control means for controlling the pulse-width modulation means in such a way that a modulation factor of the pulse-width modulation decreases as the width between the lower amplitude peak and the upper amplitude peak detected by the amplitude detection means increases.
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8. An amplitude compression device comprising:
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pulse-width modulation means for effecting pulse-width modulation on an input signal to produce a pulse-width modulated signal;
demodulation means for demodulating the pulse-width modulated signal to produce an output signal;
amplitude detection means for detecting a lower amplitude peak and an upper amplitude peak of said input signal; and
control means for controlling the pulse-width modulation means in such a way that a modulation factor of the pulse-width modulation decreases as the width between the lower amplitude peak and the upper amplitude peak detected by the amplitude detection means increases.
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9. An amplitude expansion device comprising:
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pulse-width modulation means for effecting pulse-width modulation on an input signal to produce a pulse-width modulated signal;
demodulation means for demodulating the pulse-width modulated signal to produce an output signal;
amplitude detection means for detecting a lower amplitude peak and an upper amplitude peak of said output signal; and
control means for controlling the pulse-width modulation means in such a way that a modulation factor of the pulse-width modulation increases as the width between the lower amplitude peak and the upper amplitude peak detected by the amplitude detection means increases.
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10. An amplitude compression device comprising:
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pulse-width modulation means for effecting pulse-width modulation on an input signal to produce a pulse-width modulated signal;
demodulation means for demodulating the pulse-width modulated signal to produce an output signal;
amplitude detection means for detecting a lower amplitude peak and an upper amplitude peak of said input signal; and
control means for controlling the pulse-width modulation means in such a way that a modulation factor of the pulse-width modulation increases as the width between the lower amplitude peak and the upper amplitude peak detected by the amplitude detection means increases.
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11. An amplitude compression device comprising:
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pulse-width modulation means for effecting pulse-width modulation on an input signal to produce a pulse-width modulated signal, wherein the pulse-width modulation means contains a negative feedback loop to feed back a feedback value corresponding to a fraction of the pulse-width modulated signal;
a first low-pass filter for inputting the pulse-width modulated signal to produce an output signal;
a second low-pass filter for demodulating an inversion of the pulse-width modulated signal to produce a demodulated signal;
a first hold circuit for detecting a negative peak voltage value of the demodulated signal;
a second hold circuit for detecting a positive peak voltage value of the demodulated signal;
a subtraction circuit for subtracting the negative peak voltage value from the positive peak voltage value to produce an amplitude value of the demodulated signal;
an inversion circuit for inverting an output of the subtraction circuit; and
modulation factor adjusting means for adjusting a modulation factor of the pulse-width modulation by adjusting the feedback value fed back through the negative feedback loop on the basis of the output of the subtraction circuit and an output of the inversion circuit. - View Dependent Claims (12, 13, 14)
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15. An amplitude compression device comprising:
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pulse-width modulation means for effecting pulse-width modulation on an input signal to produce a pulse-width modulated signal, wherein the pulse-width modulation means contains a negative feedback loop to feed back a feedback value corresponding to a fraction of the pulse-width modulated signal;
a low-pass filter for inputting the pulse-width modulated signal to produce an output signal;
a first hold circuit for detecting a negative peak voltage value of the input signal;
a second hold circuit for detecting a positive peak voltage value of the input signal;
a subtraction circuit for subtracting the negative peak voltage value from the positive peak voltage value to produce an amplitude value of the input signal;
an inversion circuit for inverting an output of the subtraction circuit; and
modulation factor adjusting means for adjusting a modulation factor of the pulse-width modulation by adjusting the feedback value fed back through the negative feedback loop on the basis of the output of the subtraction circuit and an output of the inversion circuit. - View Dependent Claims (16, 17, 18)
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Specification