Fiber-optic node with forward data content driven power consumption
Methods and systems for modulating an amplifier power supply to efficiently attain amplified RF output power with much lower power dissipation than existing amplifiers. In a cable television (CATV) network, a processor receives a signal to be amplified by an amplifier at a location remote from the processor. A bias point of the amplifier may be variably modulated based on peaks of an input signal to reduce amplifier dissipation.
1. A device having an amplifier operable for amplifying an input signal, the device reducing power dissipation by modulating an amplifier voltage source, the device comprising:
a first amplifier voltage source, wherein an amplifier amplifies signals with power provided via an output from the amplifier voltage source;
a second amplifier voltage source producing a waveform representing the input signal to amplify; and
an amplifier bias current control circuit driven by a bias signal generated by passing samples of the input signal to amplify through a peak detection circuit, an output from the amplifier bias current control circuit causing variable changes to a bias point of the amplifier to coincide with peaks in the input signal,
wherein the bias point of the amplifier modified by the amplifier bias current control circuit output is varied to reduce power consumption of the amplifier;
the amplifier driven by a delayed input signal adjusted in response to changes in the envelope signal of the bias signal,
wherein the delayed input signal is the input signal delayed by a number of samples for coinciding a response of the bias signal with at least one peak in the input signal; and
an output transformer of said amplifier with coupled windings for reducing resistance to common mode current fluctuations caused by the changes to the amplifier bias point.
2. The device of claim 1 , where amplification of the input signal comprises amplification of a first component of the input signal, and prior to such amplification another component of the input signal pro-distorts the first component prior to amplification.
3. The device of claim 2 , wherein the another component is based on the first component and a signal envelope of the first component.
4. The device of claim 1 , wherein the amplifier is driven by a delayed input signal having a magnitude adjusted in response to changes in the envelope signal of the bias signal.
5. The device of claim 1 , wherein pre-distortion information is transmitted to the amplifier with said input signal, the pre-distortion information based on said input signal and an envelope of said input signal.
6. The device of claim 1 , wherein the amplifier bias current control circuit provides bias to the amplifier via an inductor connected to a fixed voltage.
7. The device of claim 1 , further comprising a capacitor connected to the amplifier bias current control circuit to generate a variable voltage, wherein the variable voltage is controlled by a signal derived from the envelope of a signal output from the amplifier.