Method and apparatus of a fast digital automatic gain control circuit
First Claim
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1. An automatic gain control circuit comprising:
- an amplifier having at least a received signal and an analog gain control signal as separate inputs, wherein said amplifier amplifies said received signal by an amplification factor to generate an amplified analog signal;
an analog-to-digital converter configured to convert said amplified analog signal into an amplified digital signal;
a signal strength estimator configured to measure signal strength of said amplified digital signal;
a gain adjusting factor device configured to generate a gain adjusting factor;
a multiplier configured to multiply a digital gain control signal by said gain adjusting factor; and
a digital-to-analog converter configured to convert the digital gain control signal into said analog gain control signal,whereby said gain adjusting factor device generates said gain adjusting factor according to said signal strength, andwhereby said analog gain control signal determines said amplification factor.
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Abstract
An automatic gain control circuit with a very wide operational range, less hardware, and faster response, and more flexibility includes a signal strength estimator, a gain adjusting factor device and a multiplier. After the signal strength estimator finds signal strength, the gain adjusting factor device will generate a gain adjusting factor corresponding to the signal strength. Then the multiplier will update gain by multiplying it the gain adjusting factor.
23 Citations
11 Claims
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1. An automatic gain control circuit comprising:
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an amplifier having at least a received signal and an analog gain control signal as separate inputs, wherein said amplifier amplifies said received signal by an amplification factor to generate an amplified analog signal; an analog-to-digital converter configured to convert said amplified analog signal into an amplified digital signal; a signal strength estimator configured to measure signal strength of said amplified digital signal; a gain adjusting factor device configured to generate a gain adjusting factor; a multiplier configured to multiply a digital gain control signal by said gain adjusting factor; and a digital-to-analog converter configured to convert the digital gain control signal into said analog gain control signal, whereby said gain adjusting factor device generates said gain adjusting factor according to said signal strength, and whereby said analog gain control signal determines said amplification factor. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for automatically varying a gain control signal for a receiver, comprising the steps of:
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a) amplifying a received signal according to an adjustable amplification factor to generate an amplified analog signal, wherein said adjustable amplification factor is determined by an analog gain control signal; b) converting said amplified analog signal from analog format into an amplified digital signal; c) calculating signal strength of said amplified digital signal; d) generating a gain adjusting factor based on a predefined relation between signal strength and a reference gain adjusting factor; e) updating a digital gain control signal by multiplying said digital gain control signal by said gain adjusting factor; and f) converting said digital gain control signal to said analog gain control signal. - View Dependent Claims (9, 10, 11)
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Specification