DC detector for a transmit datapath
AssigneeAnalog Devices, Inc.
InventorsRobert D. Solanki, Christopher Mayer
Life of this patent
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Abstract
A transmitter with a DC detection circuit that can control when a modulator of the transmitter is active. When data is being transmitted, a tone introduced by a mixer in the transmit path is hidden by the data signal and has minimal effect on the transmit path. However, when there is no data, the tone can cause undesirable noise. A modulator may move the tone or noise outside of the transmitter's bandwidth. As the data can hide the tone, the DSM may only be needed when there is a DC signal. By activating the DSM only when a DC signal is detected, the extra power introduced by the modulator can be reduced while eliminating in-band noise.
Claims20
A transmitter comprising:
- a filter chain configured to process a transmit signal;
- a modulator configured to convert the transmit signal to a digital transmit signal when enabled;
- a digital-to-analog converter (DAC) configured to convert the digital transmit signal to an analog signal;
- and
- a direct current (DC) detector configured to determine a percentage of DC component within the transmit signal and to enable the modulator when the percentage of DC component satisfies a DC threshold.
A wireless device comprising:
- an antenna configured to transmit a radio frequency signal;
- and
- a transmitter configured to generate the radio frequency signal for transmission by the antenna, the transmitter comprising:
- a filter chain configured to process a transmit signal;
- a modulator configured to convert the transmit signal to a digital transmit signal when enabled;
- a digital-to-analog converter (DAC) configured to convert the digital transmit signal to an analog signal;
- and
- a direct current (DC) detector configured to determine a percentage of DC component within the transmit signal and to enable the modulator when the percentage of DC component satisfies a DC threshold.
A method of reducing power consumption in a transmitter, the method comprising:
- by a direct current (DC) detector implemented in hardware, receiving a first sample of a transmit signal within a sample window;
- receiving a second sample of a transmit signal within the sample window;
- determining that the first sample and the second sample are the same;
- responsive to the determining that the first sample and the second sample are the same, incrementing a DC count;
- determining that the DC count satisfies a DC threshold;
- and
- responsive to the determining that the DC count satisfies the DC threshold, enabling a modulator within a transmit path of the transmitter.
Dependencies are inferred from the claim text.