Signal processing circuit
AssigneeMurata Manufacturing Co., Ltd.
InventorYoshihiro Yamaguchi
Life of this patent
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Abstract
A signal processing circuit is provided that includes a capacitor coupled to a signal line to be coupled to a sensor, and coupled in series with the sensor, and a variable resistance circuit coupled in parallel with the capacitor. The variable resistance circuit and the capacitor form a high-pass filter that allows a signal having a cutoff frequency or higher to pass through the high-pass filter. In the variable resistance circuit, a resistance value is set to a first resistance value when a target signal having a peak component on a time axis is allowed to pass through the high-pass filter, and the cutoff frequency at the first resistance value is 1/10 or less of a frequency of the peak component.
Claims18
A signal processing circuit comprising:
- a capacitor coupled in series to a signal line to be coupled to a sensor;
- and
- a variable resistance circuit coupled in parallel with the signal line, the variable resistance circuit including a switched capacitor that includes a capacitor and a first switch,
- wherein the variable resistance circuit and the capacitor form a high-pass filter that is configured to pass a frequency that is equal to or higher than a cutoff frequency,
- wherein, in the variable resistance circuit, a resistance value is set to a first resistance value when a target signal having a peak component on a time axis is allowed to pass through the high-pass filter, and the cutoff frequency at the first resistance value is 1/10 or less of a frequency of the peak component, and
- wherein the resistance value of the variable resistance circuit is set to a second resistance value that is lower than the first resistance value when the target signal does not pass through the high-pass filter.
A signal processing circuit comprising:
- a capacitor coupled in series to a signal line to be coupled to a sensor;
- and
- a variable resistance circuit coupled in parallel with the signal line,
- wherein the variable resistance circuit and the capacitor form a high-pass filter that is configured to pass a signal having a frequency that is equal to or higher than a cutoff frequency,
- wherein, in the variable resistance circuit, a resistance value is set to a first resistance value when a target signal having a peak component on a time axis is allowed to pass through the high-pass filter, and the cutoff frequency at the first resistance value is 1/10 or less of a frequency of the peak component,
- wherein the resistance value of the variable resistance circuit is set to a second resistance value that is lower than the first resistance value when the target signal does not pass through the high-pass filter, and
- wherein the variable resistance circuit further-includes;
- a resistor,
- a third switch coupled in parallel with the resistor, and
- a buffer amplifier coupled in series with the third switch,
- wherein the first resistance value is changed to the second resistance value by turning on the third switch.
Dependencies are inferred from the claim text.