Abstract: A radio frequency transmitter having a tunable radio frequency signal generator and an amplifier coupled to the tunable radio frequency signal generator. An aerial is coupled to the amplifier and transmits the amplified radio frequency signal, which may then be received by various radio receivers. The aerial has an output voltage and an impedance. The impedance includes inductive and capacitive reactances. In order to maximize the output voltage of the aerial, an adjustable inductor is coupled to it. The adjustable inductor includes a pair of tuning coils with adjustable ferrite cores. A sampler measures the output voltage of the antenna. The sampled output voltage of the aerial is converted to a digital signal and then compared with a DC reference voltage produced by a processing unit in a comparator. The processing unit is coupled to the comparator and the adjustable inductor and receives the converted signal and analyses its amplitude.

Abstract: A radio frequency transmitter, amplitude modulated, having a single tuner that tunes the frequency oscillator, the isolating filter and the antenna impedance, all at the same time. The transmitter includes a tunable carrier generator for generating a carrier signal of a desired frequency, and a carrier isolator for filtering the carrier signal so as to ensure a clean, isolated carrier signal. A power amplifier is included for amplifying the signal from the carrier isolator. The power amplifier has a certain output impedance. An antenna is connected for transmitting the amplified signal from the power amplifier. The antenna also has a certain impedance. The transmitter further includes an impedance matching device connected between the antenna and the power amplifier for matching the antenna impedance and the power amplifier impedance. Finally, a single control knob is provided for simultaneously controlling the tunable carrier generator, the carrier isolator and the impedance matching device.