Radio transmitter distortion reducing techniques
AssigneeTRW Inc.
InventorMichael H. Myers
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Abstract
The non-linearity of a power amplifier (12) and a radio frequency variable attenuator (44) are reduced by providing multiplying factors generated by a signal processor (32) and applied to the multiplying function of the attenuator (44). As a result, an input signal can be transmitted with increased accuracy which meets FAA standards for aviation radio transmission.
Claims18
Apparatus for reducing distortion in a transmitter radio signal suitable for use in an aviation radio transmitter comprising a component defining a first nonlinear transfer function, said transmitter transmitting within a predetermined range of frequencies, said apparatus comprising in combination:
- a source of an input signal containing information to be transmitted;
- a source of multiplying factors;
- a signal converter comprising an attenuator arranged to perform a multiplication function with said multiplying factors on said input signal to generate a second signal, said multiplication function containing a second nonlinear transfer function, said multiplying factors defining a third nonlinear transfer function related to said first nonlinear transfer function and a fourth nonlinear transfer function related to said second nonlinear transfer function so that said input signal is modified to adjust for said first nonlinear transfer function and said second nonlinear transfer function.
A method of reducing distortion in a transmitter radio signal suitable for use in an aviation radio transmitter comprising a component defining a first nonlinear transfer function, said transmitter transmitting within a predetermined range of frequencies, said method comprising in combination:
- receiving an input signal containing information to be transmitted;
- generating one or more first signals representing multiplying factors;
- performing an attenuating multiplication function with said multiplying factors on said input signal to generate a second signal, said multiplication function containing a second nonlinear transfer function, said multiplying factors defining a third nonlinear transfer function related to said first nonlinear transfer function and a fourth nonlinear transfer function related to said second nonlinear transfer function so that said input signal is modified to adjust for said first nonlinear transfer function and said second nonlinear transfer function;
- and
- passing said second signal through said component to reduce distortion in the transmitter radio signal.
Dependencies are inferred from the claim text.