Abstract: An edge seal structure and fabrication method are described. The edge seal structure includes a high impedance substrate containing a base material and a grounded floating edge seal that is on the substrate but is isolated from the base material. The edge seal contacts a first doped well in the substrate that has the same conductivity type as and is more heavily doped than the base material. The first doped well is in a second doped well that has a different conductivity type than the first doped well. The first and second doped wells and the base material form back-to-back series connected diodes. The wells are effectively connected to power and ground such that the diodes are reverse-biased. The edge seal is formed by a stack of conductive layers, at least some of which are surrounded by a stack of insulating layers.

Abstract: A buck or boost (BOB) power converter circuit. A buck converter is cascaded with a boost converter to form a buck or boost circuit (20). The BOB converter is controlled by a controller (26) such that only the buck or boost converter is operating at any given time. A reference signal Vref can be applied to the controller (26) such that the output voltage from the converter closely tracks the reference signal. Positive and negative ramp signals are generated and an error feedback signal is compared with the ramp signals to control the output in accord with Vref. This is useful in application of the output voltage as the power supply to an RF Power Amplifier (16) so that the reference signal can represent the envelope of a signal to be transmitted and the RF PA (16) can operate at high efficiency.

Abstract: In a communication unit a receiver (104) receives a modulated signal (118), and produces a received signal (120) having a parameter. The receiver (104) has a discontinuous receive mode of operation, wherein the receiver (104) is permitted to be turned on and off. Receiver circuitry (105) receives the received signal (120), and produces an output signal (124) having a parameter. A controller (110) adjusts a value of the parameter of the output signal (124), responsive to a value of the parameter of the received signal (120), during the times when the receiver (140) is turned on; and holds the value of the parameter of the output signal (124), responsive to the value of the parameter of the received signal (120), at the time when the receiver (104) is turned off. The present invention advantageously minimizes the turn on time for the receiver (104) operating in a discontinuous receive mode to save current drain.

Abstract: A method and apparatus for integrating a plurality of analog input signals. A first integrator(725) having a first pole frequency integrates a first of the input signals and a second integrator(730) having a second pole frequency different than the first pole frequency integrates a second of the input signals. A summer(735) is connected to the first and second integrators to then sum the integrated first and second signals and provide a composite integrated signal prior to transmitting a communications signal.

Abstract: An apparatus and a method for minimizing the turn on time for a receiver operating in a discontinuous receive mode. In a communication unit the receiver receives a signal (118) having desirable data (word A) and undesirable data (word B). The receiver (104) has a discontinuous receive mode of operation wherein the receiver (104) is turned on when expecting the desirable data (word A) and turned off when expecting the undesirable data (word B). A duration of time that the receiver (104) has been turned off is determined. The receiver (104) is turned on at time prior to the arrival of the desirable data (word A) responsive to the duration of time that the receiver (104) has been turned off. The present invention advantageously minimizes the turn on time for the receiver (104) operating in a discontinuous receive mode to save current drain.

Abstract: Radiotelephones often are powered by batteries (12). When a radiotelephone is bumped, the battery (12) can lose electrical contact with the radiotelephone. When power is interrupted (40), a timer is started (42). When the power is reapplied (44), the timer is sampled (46) and compared against a predetermined period of time. If the power was interrupted for a short time, then the radiotelephone is turned on (50). If the power was interrupted for a long time, then the radiotelephone stays off (48). The timer in the circuit is implemented as an RC circuit (26) starts to discharge. If the voltage level falls below Vref, the radiotelephone will not turn on when the power is reapplied.

Abstract: A wedge-shaped receptacle for mounting a noise cancelling microphone transducer (105) and a ringer alert transducer (107) within a housing (101) is disclosed. The receptacle (111) is molded from a flexible material providing efficient assembly of the transducers within two apertures in the receptacle (129 and 133). Gaskets (137 and 145), molded as part of the receptacle, provide an acoustic and weatherproof seal between the receptacle (111) and the housing (101) for each transducer. The two apertures (129 and 133), providing acoustic interface for the ringer alert transducer (107) and the microphone transducer (105), share the same opening (113) in the front face of the housing (101). The aperture (133) for the noise cancelling microphone (105) is also open to a second opening (115) in the bottom face of the housing (101) to cancel background noise. The receptacle includes channels (201 and 202) which allow back pressure release for the ringer alert transducer (107 ).

Abstract: Improved speakerphones (120 and 130 in FIG. 1) for both radio (112) and landline (138) telephones are described. The improved speakerphones (120 and 130) each include a microphone (102 and 132), a speaker (104 and 134) and unique control circuitry (106 and 136). The control circuitry of the improved speakerphone (200 in FIG. 2) interfaces a microphone (250) to a transmit signal (220) and speaker (260) to a receive signal (222) of a duplex communication path, such as a radio channel or telephone line. Variable gain stages (212 and 202) amplify and attenuate the speaker and microphone audio paths, respectively, in response to a gain control signal (223) from control logic (230).