Precursor Rejection Filter
AssigneeApple Inc.
InventorsShachar Shayovitz, Michael Kerner, Zohar Agon
Life of this patent
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Abstract
A precursor rejection filter is disclosed. A digital filter is coupled to receive packets from a data source. The filter may operate in one of a first mode or a second mode. In the first mode, the filter may receive communications packets. When operating in the second mode, the filter may receive sensing packets. Furthermore, when operating in the second mode, the filter may cause a precursor of the equivalent impulse response of the transmitter to be attenuated without attenuating the main lobe of the of the equivalent impulse response of the transmitter.
Claims19
An apparatus comprising:
- a data source configured to convey packets;
- a filter including:
- N delay elements, wherein N is an integer value;
- K multipliers, wherein K is an integer value, and wherein a first one of the K multipliers is coupled an input to a first one of the N delay elements, and wherein the remaining ones of the K multipliers are coupled to outputs of corresponding ones of the N delay elements;
- and
- K multiplexers coupled to provide coefficients to the K multipliers, wherein ones of the K multiplexers are coupled to receive one of a first plurality of coefficients on a respective first input and one of a second plurality of coefficients on a respective second input;
- and
- control circuitry configured to provide selection signals to the K multiplexers to cause respective ones of the first plurality of coefficients to be provided to the K multipliers responsive to the data source conveying communication packets to the filter, and further cause respective ones of the second plurality of coefficients to be provided to the K multipliers responsive to the data source providing a sensing packet to the filter.
The apparatus as recited in claim 1 further comprising a summing circuit coupled to respective outputs of of the K multipliers, wherein the summing circuit is configured to generate a sum of values provided from the N delay elements and the input to the first one of the N delay elements. (Original) The apparatus as recited in claim 6, further comprising an output multiplexer, wherein the output multiplexer includes a first coupled to receive the sum of values from the summing circuit and a second input coupled to a bypass path, the bypass path being coupled to an input of the filter.
A method comprising:
- conveying, from a data source, packets to a filter, the filter including:
- N delay elements, wherein N is an integer value;
- K multipliers, where K is an integer values, and wherein a first one of the K multipliers is coupled an input to a first one of the N delay elements, and wherein the remaining ones of the K multipliers are coupled to outputs of corresponding ones of the N delay elements;
- and
- K multiplexers coupled to provide coefficients to the K multipliers, wherein ones of the K multiplexers are coupled to receive one of a first plurality of coefficients on a respective first input and one of a second plurality of coefficients on a respective second input;
- providing the first plurality of coefficients from the K multiplexers to respectively coupled ones of the K multipliers responsive to the data source conveying packets of a first type to the filter;
- and
- providing the second plurality of coefficients from the K multiplexers to respectively coupled ones of the K multipliers responsive to the data source conveying packets of a second type to the filter.
A system comprising:
- analog transmitter circuitry configured to wirelessly transmit a wireless signal, wherein the wireless signal is based on an a received analog signal;
- a digital-to-analog converter (DAC) coupled to provide an analog signal to the analog transmitter circuitry, wherein the DAC is configured to convert a digital value into the analog signal;
- and
- a filter coupled to receive packets from a data source, wherein the filter is configured to operate in a first mode when communications packets are received from the data source, and configured to operate in a second mode when sensing packets are received from the data source, wherein the filter is configured to, when operating in the second mode, cause a precursor in the analog signal to be attenuated without attenuating a main lobe or post cursor of the analog signal, wherein the filter is configured to generate and provide the digital value to the DAC.
Dependencies are inferred from the claim text.