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 power supply, the device comprising:
a first amplifier power supply, wherein an amplifier amplifies signals with power provided via an output from the first amplifier power supply; and
a second amplifier power supply driven by a bias signal generated by passing samples of the input signal to amplify through a peak detection circuit, a second amplifier power supply output 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 second amplifier power supply output is varied to reduce power consumption of the amplifier;
a linearizer that receives a delayed input signal and an envelope signal of the bias signal and applies a linearization function to the delayed input signal for driving the amplifier by the 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 pre-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 first component and the another component have an associated delay between them.
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 second amplifier power supply 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 second amplifier power supply 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.