Transmitter coupled active filter
AssigneeXetron Corporation
InventorEugene A. Janning
Life of this patent
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Abstract
The high power (10-1000 W) modulated carrier of a noisy transmitter is attenuated and amplitude limited and is used to control a power oscillator which regenerates the carrier and modulations without the loss of power. The power oscillator is slaved in frequency to the amplitude limited and attenuated signal, and it follows any phase or frequency modulation present thereon. Noise components appearing on the original carrier fall outside of the information passband of the power oscillator loop and therefore are not reproduced. The noise free output from the power oscillator is then A.M. modulated prior to power amplication and transmission. The oscillator operates at relatively high power (1 watt) and is automatically digitally coarse tuned and analog fine tuned.
Claims21
In a transmission system, the combination comprising:
- an R.F. transmitter having a high power original carrier output with signal modulations and broadband noise thereon;
- means for dissipating said high power original carrier output to a relatively low level;
- a tunable power oscillator for regenerating said carrier, said oscillator having a low noise output;
- comparison circuit means for comparing said low level original carrier with said regenerated carrier and for automatically tuning said power oscillator to the frequency of said original carrier in response to a difference between said carriers, said comparison circuit means including means responsive to said low level original carrier to derive a voltage proportional to said signal modulations for modulating said oscillator;
- and
- means for amplifying the output of said power oscillator to a predetermined high power level.
The combination comprising:
- a high power transmitter having an original carrier modulated with signal and containing noise;
- a tunable oscillator for producing a regenerated carrier;
- means for attenuating the power of said modulated original carrier to produce an attenuated carrier;
- means for amplitude limiting said attenuated carrier;
- digital means for automatically coarse tuning said oscillator in response to a difference in frequency between said regenerated carrier and said attenuated carrier;
- analog means for fine tuning said oscillator in response to a difference in frequency between said attenuated carrier and said regenerated carrier, said analog means including means for frequency and/or phase modulating said regenerated carrier;
- means for amplitude detecting said attenuated carrier to derive the amplitude modulations thereof;
- means for modulating said regenerated carrier with said amplitude modulations;
- and
- means for power amplifying said modulated regenerated carrier.
Dependencies are inferred from the claim text.