Dynamic error vector magnitude duty cycle correction
First Claim
Patent Images
1. An apparatus comprising:
- an amplifier configured to amplify an input signal;
a low pass filter configured to receive an indication of a duty cycle of the amplifier and to generate a correction signal based at least partly on the indication of the duty cycle of the amplifier, the indication of duty cycle being a binary signal having an activated state corresponding to the amplifier being enabled and a deactivated state corresponding to the amplifier being disabled; and
a bias circuit configured to generate a bias signal based at least partly on the correction signal such that changes in the bias signal are inversely proportional to changes in the duty cycle of the amplifier, and the bias circuit configured to bias the amplifier using the bias signal so as to compensate for a variation in gain of the amplifier from thermal effects as the duty cycle of the amplifier changes.
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Abstract
Aspects of this disclosure relate to dynamic error vector magnitude (DEVM) compensation. In one embodiment, an apparatus includes an amplifier, a low pass filter, and a bias circuit. The amplifier, such as a power amplifier, can amplify an input signal. The low pass filter, such as an integrator, can generate a correction signal based at least partly on an indication of a duty cycle of the amplifier. The indication of the duty cycle of the amplifier can be an enable signal for the amplifier, for example. The bias circuit can generate a bias signal based at least partly on the correction signal and provide the bias signal to the amplifier to bias the amplifier.
45 Citations
19 Claims
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1. An apparatus comprising:
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an amplifier configured to amplify an input signal; a low pass filter configured to receive an indication of a duty cycle of the amplifier and to generate a correction signal based at least partly on the indication of the duty cycle of the amplifier, the indication of duty cycle being a binary signal having an activated state corresponding to the amplifier being enabled and a deactivated state corresponding to the amplifier being disabled; and a bias circuit configured to generate a bias signal based at least partly on the correction signal such that changes in the bias signal are inversely proportional to changes in the duty cycle of the amplifier, and the bias circuit configured to bias the amplifier using the bias signal so as to compensate for a variation in gain of the amplifier from thermal effects as the duty cycle of the amplifier changes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An electronically implemented method of biasing an amplifier, the method comprising:
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integrating an indication of a duty cycle of the amplifier to generate a dynamic correction signal, the indication of duty cycle being a binary signal; generating a bias signal based at least partly on the dynamic correction signal such that changes in the bias signal are inversely proportional to changes in the duty cycle of the amplifier; and biasing the amplifier using the bias signal so as to compensate for a variation in gain of the amplifier from thermal effects as the duty cycle of the amplifier changes. - View Dependent Claims (14)
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15. A circuit for biasing an amplifier, the circuit comprising:
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a duty cycle tracking circuit configured to generate a signal representative of a duty cycle of the amplifier over time based at least partly on a state of an enable signal that enables the amplifier to amplify an input signal and to adjust the signal representative of the duty cycle of the amplifier over time as the duty cycle of the amplifier changes; and a bias circuit in communication with the duty cycle tracking circuit, the bias circuit configured to generate a bias signal based at least partly on the signal representative of the duty cycle over time such that changes in the bias signal are inversely proportional to changes in the duty cycle of the amplifier and to provide the bias signal to the amplifier to bias the amplifier. - View Dependent Claims (16, 17, 18, 19)
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Specification