Abstract: A crosspoint switch including a switch matrix modules and programming features. A switch matrix modules include input lines tied to inputs of the switch through precompensation networks. The programming features include user initialization states and reduced and grouping command configuration operations.

Abstract: A crosspoint switch including a switch matrix modules and programming features. A switch matrix modules include input lines tied to inputs of the switch through precompensation networks. The programming features include user initialization states and reduced and grouping command configuration operations.

Abstract: A crosspoint switch including a switch matrix modules and programming features. A switch matrix modules include input lines tied to inputs of the switch through precompensation networks. The programming features include user initialization states and reduced and grouping command configuration operations.

Abstract: An AFC switch circuit is controlled by an select input logic signal for providing a selected output signal to control the local oscillator in a miniature FM receiver. The output signal has a voltage equal to either an AFC signal voltage for AFC operation of the receiver, or a reference voltage for synthesized operation of the receiver. The AFC switch circuitry employs bipolar transistors in current mirror configurations to minimize voltage offset and to enhance isolation between the unselected input and the output while operating on a power supply voltage less than 3 volts.

Abstract: A microcircuit bias-current supply in a wristwatch-pager. An FM-radio receiver in a microcircuit paging device operates intermittently with a short on-time and long off-time to reduce power consumption and preserve battery life. The bias-supply circuit distributes predetermined bias currents to a plurality of functional circuit areas of the microcircuit die, the bias currents being disabled during off-time of the receiver such that the current drain of the entire microcircuit is virtually zero, being in the range of nanoamps. The inefficiencies and disadvantages of a series switch to stitch power on and off are eliminated by providing a plurality of switched current sources which perform the dual function of circuit biasing and current switching.

Abstract: A microcircuit bias-current supply in a wristwatch-pager. An FM-radio receiver in a microcircuit paging device operates intermittently with a short on-time and long off-time to reduce power consumption and preserve battery life. Ths bias-supply circuit distributes predetermined bias currents to a plurality of functional circuit areas of the microcircuit die, the bias currents being disabled during off-time of the receiver such that the current drain of the entire microcircuit is virtually zero, being in the range of nanoamps. The inefficiencies and disadvantages of a series switch to switch power on and off are eliminated by providing a plurality of switched current sources which perform the dual function of circuit biasing and current switching.

Abstract: A circuit for temperature compensation of a varactor voltage controlled oscillator control signal includes a proportional to absolute temperature (PTAT) current source and an adjustable, temperature stable current source. The difference between these two current sources defines an offset current. The varactor control signal voltage is shifted by a predetermined reference voltage and offset by an offset voltage proportional to the offset current, in a differential amplifier portion of the circuit, to provide a tuning signal for controlling the varactor so as to compensate for the varactor capacitance temperature drift. The adjustable, temperature stable current source allows tuning the circuit in order to precisely tune the VCO to a desired frequency under a predetermined set of operating conditions in order to correct component and process variations.

Abstract: A direct conversion FM receiver that includes AC coupling and automatic gain control employs an offset frequency at the first local oscillator. The offset frequency prevents the frequency spectrum occupied by the signal modulation from being affected by AC coupling. The offset frequency is chosen so that it translates the frequency spectrum of the received signal outside the DC notch created in the spectrum by the AC coupling. To conserve battery supplied power, an error amplifier coupled between the output of the receiver and the first local oscillator maintains the offset frequency after it has been established by a frequency synthesizer, which is then turned off.

Abstract: Circuitry is disclosed for staggering the onset of gain reduction in a series of cascaded gain stages as a function of received signal strength. The staggering is effected by controlling the area ratio between corresponding components in two or more AGC control circuits whose topologies are otherwise identical. The technique is particularly well suited for use in radio receivers fabricated in integrated circuit form.