Dynamic high-pass filter cut-off frequency adjustment
AssigneeApple Inc.
InventorsXinping Zeng, Mohit Narang, Peter M. Agboh, Vusthla Sunil Reddy
Life of this patent
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Abstract
A transceiver that allows dynamic high-pass filter (HPF) cut-off frequency adjustment may include a mixer circuit to mix a local oscillator (LO) signal with a receive (RX) signal received from a transmitter to generate a baseband signal. The transceiver may further include a high-pass filter (HPF) having an adjustable cut-off frequency that is used to reduce a DC offset of the baseband signal. A control circuit can dynamically control components of the HPF to set the adjustable cut-off frequency at a first frequency during a first time period and at a second frequency during a second time period.
Claims21
A transceiver comprising:
- a mixer circuit configured to mix a local oscillator (LO) signal with a receive (RX) signal to generate a baseband signal;
- a high-pass filter (HPF) having an adjustable cut-off frequency configured to reduce a DC offset of the baseband signal;
- and
- a control circuit configured to dynamically control components of the HPF to set an adjustable cut-off frequency at a first frequency during a first time period and at a second frequency during a second time period,
- wherein the first time period comprises a pre-transmit time period and a post-transmit time period, wherein the pre-transmit time period comprises a time interval prior to transmission by the transceiver in response to receiving a first signal from a transmitter of a second transceiver, and the post-transmit time period comprises a time period subsequent to the transmission by the transceiver in response to receiving the first signal from the transmitter of the second transceiver.
A communication system comprising:
- a transceiver configured to communicate with an other transceiver, the transceiver comprising:
- a demodulator configured to demodulate a signal transmitted by the other transceiver and to generate a baseband signal;
- a high-pass filter (HPF) configured to reduce a DC offset of the baseband signal;
- and
- a controller configured to dynamically control an adjustable cut-off frequency of the HPF by:
- setting an adjustable cut-off frequency to a first frequency during a first time period and to a second frequency during a second time period,
- wherein the first time period comprises a pre-transmit time period and a post-transmit time period, wherein the pre-transmit time period comprises a time period prior to transmission by the transceiver in response to receiving a first signal from a transmitter of the other transceiver, and the post-transmit time period comprises a time period subsequent to the transmission by the transceiver in response to receiving the first signal from the transmitter of the other transceiver.
A method comprising:
- configuring a mixer circuit of a first transceiver to demodulate a signal received from a second transceiver and to generate a baseband signal;
- coupling an adjustable high-pass filter (HPF) to an output node of the mixer circuit to reduce a DC offset of the baseband signal;
- and
- configuring a control circuit to dynamically adjust the adjustable HPF by setting an adjustable cut-off frequency at a first frequency during a first time period and at a second frequency during a second time period,
- wherein the first time period comprises a pre-transmit time period and a post-transmit time period, wherein the pre-transmit time period comprises a time interval prior to transmission by the first transceiver in response to receiving the first signal from a transmitter of the second transceiver, and the post-transmit time period comprises a time period subsequent to the transmission by the first transceiver in response to receiving the first signal from the transmitter of the second transceiver.
Dependencies are inferred from the claim text.