Abstract: An oscillator-transmitter (100) includes an input tank circuit (101) coupled between a first amplifier (103) and a second amplifier (105) configured in an oscillator arrangement. An output tank circuit (107, 109, 111 ), for radiating radio-frequency energy, is coupled between outputs (106, 110) of the first and second amplifiers (103, 105). The output tank circuit (107, 109, 111) radiates energy provided by both the first and second amplifiers (103, 105).

Abstract: A remote signal transmitter capable of producing a radio frequency signal for implementation of access commands including an oscillator circuit which is alternatively capable of producing a fixed frequency signal or a modulated frequency signal as a result of selective biasing by a microprocessor. The oscillator signal is broadcast as a series of data bits which achieve a unique signature as a result of the sequence in which the fixed and modulated signals are broadcast. In addition, the signals may be broadcast for various durations which are representative of digital zeros and ones. A receiver detects the presence of the fixed and modulated signals and digital values thereof by comparison with stored values. In this manner a friend/foe screen is implemented which then permits implementation of a command contained in the remainder of the data bit stream.

Abstract: An electrically tuned super-regenerative receiver (10) comprises a feedback type oscillator having a signal output and a signal input, phase shift components (30) connected in a feedback loop for coupling the signal output to the signal input to cause oscillations, and a quench oscillator (35) coupled to the signal input for switching the oscillator between an oscillating and a non-oscillating condition. A variable capacitance device (40), such as a varactor diode, is connected between the signal output and a reference potential (21), and a microprocessor (105) provides a tuning voltage (42) which is applied at the signal output for varying the current in the varactor diode, thereby varying the oscillator center operating frequency. The oscillator center operating frequency is detected by a spectrum analyzer (112) and compared to a desired center operating frequency by a controller (118).