Abstract: A method and arrangement for electronically bandswitching a radio (100) is described which includes at least a receiver (110, 111), a PLL (120), and a fully synchronized, programmable counter as a frequency divider (140) that is coupled between the receiver and the PLL. This fully synchronized divider (140) provides an output signal (143) at a lower frequency with minimal harmonic energy and improves the sideband noise performance as the divisor increases. When the radio also includes a transmitter (104), stepped attenuators (128, 132) are also included for adjusting the modulation of the PLL (120) when in the transmit mode.The PLL includes at least a reference signal generator (121, 122), a phase detector (124), and a voltage controlled oscillator (127) having an output (129) coupled, via a feedback path, to a second input (131) of the phase detector (124).

Abstract: A dual FET oscillator includes a first J-FET and a second J-FET connected to it as a source follower. A turned circuit is connected to the gate of the first J-FET and to the second J-FET. Bias voltage is supplied to both J-FET's. Schottky diodes are connected to both J-FET's to limit gate-source voltage.

Abstract: A Ga As FET oscillator includes an FET having gate-drain and source connections. A tuned circuit is connected to the FET gate. Bias voltage is supplied to the FET. A parallel-connected resistor and capacitor is connected to the FET source. A Schottky diode is connected across the FET gate-source junction and the parallel connected resistor and capacitor, with its anode connected to the FET gate and its cathode connected to the resistor and capacitor. The Schottky diode limits the positive voltage across the gate-source junction of the Ga As FET to prevent gate-source current flow.

Abstract: A variable capacitance circuit includes a varactor having an anode side and a cathode side. A first variable bias voltage is applied to one of the sides and one of a plurality of voltages is applied as a second bias voltage to the other side for controlling the capacitance of the varactor. A voltage multiplier circuit connected to a voltage divider network is used for supplying the plurality of voltages. A decoder is responsive to input signals for selecting and applying one of the multiple voltage outputs. The variable capacitance circuit is used in a voltage controlled oscillator of a frequency synthesizer for providing extended frequency range.

Abstract: A radio receiver from antenna to detector designed to be realized substantially on an integrated-circuit chip comprises a single tunable oscillator and a plurality of mixers. An input signal from an antenna is connected as an input to a first mixer and mixed with a signal derived from the oscillator. The signal may be taken directly, may be multiplied to a desired level or may be divided to a desired level. A particular output from the first mixer is selected by a first tunable filter. The output of the first tunable filter is taken as an input to a second mixer where it is mixed with a second signal derived from the oscillator. The process of mixing and application of the mixed signal to a tunable filter to select a desired frequency is continued as needed until the signal is reduced to a desired intermediate frequency range where it is amplified as needed to a level sufficient to drive a discriminator.

Abstract: A broadband isolator design wherein the amount of insertion loss may be traded for bandwidth and possibly reduced circuit complexity. The isolator may employ two windings or conductors with the neutralizing element connected across the input-output terminals, or may have a third winding placed to bisect the angle between the other windings and the neutralizing element coupled across this third winding. The angle between the windings and the isolator interconnection determine the specific bandwidth and insertion loss.