Automatic gain control method and apparatus
AssigneeIndustrial Technology Research Institute
InventorHsin-An Hou
Life of this patent
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Abstract
Automatic gain control method and apparatus control a gain of a received signal. While the gain is adjusted and thus converges, a finding mode is entered to additionally change the gain at least once according to at least one characteristic value obtained from a relationship between the gain and time, such that the gain approaches a target level. In other embodiments, a tracking mode is further entered to periodically adjust the gain at a period greater than that before when signal strength is being tracked to reduce noise energy introduced. Hence, the embodiments can improve a gain converging speed and reduce the influence of the noise on the communication system in a dynamic receiving environment, and thus enhance the signal receiving performance.
Claims28
An automatic gain control method, comprising:
- (a) adjusting a gain of a received signal in a finding mode, while additionally changing the gain at least once according to a variation condition of a gain curve of the gain such that the gain approaches a target gain level, wherein the step of additionally changing the gain comprises the sub-steps of:
- detecting at least one characteristic point of the gain curve, wherein the at least one characteristic point of the gain curve comprises at least one point of the gain curve, at which a first order or a second order differential of the gain curve with respect to time is equal to zero substantially;
- determining a switching value for making the gain approach the target gain level according to a gain of the gain curve corresponding to the at least one point;
- and
- setting the gain to a new gain according to the switching value and making the new gain become valid;
- wherein the detecting, determining and setting sub-steps are performed at least once.
An automatic gain control apparatus, comprising:
- a variable gain amplification unit for controlling a received signal according to a gain and thus generating a first signal;
- an analog-to-digital converter for generating a digital signal according to the first signal;
- and
- a main control unit for generating a gain control signal according to the digital signal and a target level, wherein the gain of the variable gain amplification unit is adjusted according to the gain control signal,
- wherein when the main control unit operates in a finding mode, while the gain is being adjusted, the main control unit additionally changes the gain at least once according to at least one characteristic value, obtained from a relationship between the gain and time, such that the gain approaches a target gain level;
- wherein the at least one characteristic value comprises at least one gain corresponding to at least one point of a gain curve formed by the relationship between the gain and time, at which a first order or a second order differential of the gain curve with respect to time is equal to zero substantially, and the main control unit additionally changes the gain at least once according to the at least one gain corresponding to the at least one point of the gain curve.
Dependencies are inferred from the claim text.