US 11,309,869 B1 · Oscillating signal generator and filter circuit

Abstract

A filtering circuit includes a filter, a frequency divider, and a control circuit. The filter is configured to generate a first oscillating signal according to a control signal in a first mode, and perform a filtering process according to the control signal in a second mode. A frequency of the first oscillating signal is determined according to the control signal. The frequency divider is coupled to the filter and configured to divide the frequency of the first oscillating signal to generate a frequency-divided signal. The control circuit is coupled to the filter and the frequency divider, and configured to compare a frequency of the frequency-divided signal and a frequency of a second oscillating signal so as to adjust the control signal in the first mode. A center frequency of a passband of the filter in the second mode is determined according to the adjusted control signal.

Claims20

Dependent claims

A filtering circuit, comprising:

a filter, configured to generate a first oscillating signal according to a control signal in a first mode, and perform a filtering process according to the control signal in a second mode, wherein a frequency of the first oscillating signal is determined according to the control signal;
a frequency divider, coupled to the filter and configured to divide the frequency of the first oscillating signal to generate a frequency-divided signal;
and
a control circuit, coupled to the filter and the frequency divider, and configured to compare a frequency of the frequency-divided signal and a frequency of a second oscillating signal so as to adjust the control signal in the first mode, wherein a center frequency of a passband of the filter in the second mode is determined according to the adjusted control signal,
wherein the filter is configured to receive an input signal in the second mode, and perform the filtering process on the input signal according to the passband, and the input signal is uncoupled from the filter in the first mode.

2 more elements

An oscillating signal generation circuit, comprising:

a filtering circuit, configured to generate a first oscillating signal in a first mode, receive a second oscillating signal to adjust a frequency of the first oscillating signal, and perform a filtering process on an input signal to generate an output signal in a second mode, wherein a center frequency of a passband of the filtering circuit is determined according to the frequency of the adjusted first oscillating signal;
and
an oscillator circuit, coupled to the filtering circuit and configured to receive the second oscillating signal to generate the input signal,
wherein the input signal is uncoupled from the filtering circuit in the first mode.

1 more element

Dependencies are inferred from the claim text.

Oscillating signal generator and filter circuit

Life of this patent

Oscillating signal generator and filter circuit

Life of this patent

Abstract

Claims20