Low latency for start of initial automatic gain control for data in digital signal processing
AssigneeIntel Corporation
InventorsQiang Wu, Gene A. Frederiksen
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Abstract
An apparatus and method for controlling the AGC in a receiver is described. Samples of the input signal are compared to the upper and lower threshold values which are defined by the dynamic range of the A-to-D converter. These samples are recorded and used in determining whether to count-up or count-down in counters prior to the time the signal is detected. These counts provide, in effect, a history of what has occurred prior to signal detection and are used in computing an AGC gain. The gain can be computed more quickly since there is zero latency in starting the calculation for correcting the AGC.
Claims22
A digital signal processor comprising:
- an analog front end including an analog-to-digital converter for receiving an input signal;
- a digital base-band processor having a latency period for detecting a signal, coupled to the analog front end;
- a shift register for tracking data representing the relative amplitude of samples of the input signal;
- a gain control counter controlled by a current relative amplitude of sample of the input signal and an output from the shift register, coupled to the shift register;
- and
- a gain control circuit coupled to the counter for controlling gain of the input signal.
In a digital signal processor having a latency period for detecting a signal, an improvement comprising:
- memory means for recording a history of the relative amplitude of samples of an input to the processor;
- and
- gain control means for controlling the gain of the input to the processor based upon the current amplitude of the input to the processor and the relative amplitude of prior input samples recorded in the memory means.
A method for controlling gain in a digital signal processor comprising:
- tracking data representing the relative amplitude of an input signal;
- and
- controlling the gain by considering a current amplitude and a prior amplitude from the tracked data.
Dependencies are inferred from the claim text.