US 8,786,784 B2 · Pseudo digital gain control for broadband tuner

Abstract

A digital level control circuit, such as an Automatic Gain Control, includes a plurality of digitally selectable signal levels with transitions between levels gradually varied to avoid signal output level discontinuities. An up/down counter may be used to incrementally stepwise transition an output signal between the digitally selectable output levels. Stepwise application of a control signal to the appropriate switching elements (e.g., FETs) forming an attenuator circuit may be implemented to moderate a switching time of the switching elements to provide a more gradual transition between element operating states. A deglitch circuit may be employed to latch the switching elements to achieve the desired state at the end of a desired switching transition period.

Claims12

Dependent claims

A level control circuit comprising:

a detector configured to detect a change in level value defined by a digital level control signal;
and
a moderator configured to monotonically change a level of an input signal over some predefined transition period in response to said digital level control signal so as to achieve a desired output signal level by:
determining a desired configuration of switching element states to effectuate said desired signal level, and
selectively supplying a sequence of monotonically changing control voltages to ones of said switching elements to transition between an initial configuration and said desired configuration;
and
a deglitch circuit connected to said moderator and to said switching elements, said deglitch circuit configured to coordinate control signals between said moderator and said switching elements such that a minimum number of transitions are permitted to occur at one time.

4 more elements

Dependencies are inferred from the claim text.

Pseudo digital gain control for broadband tuner

Life of this patent

Pseudo digital gain control for broadband tuner

Life of this patent

Abstract

Claims12