Abstract: A method includes: receiving a burst including payload and a synchronization field, wherein the synchronization field contains a synchronization pattern; selecting, from a plurality of expected synchronization patterns, a target synchronization pattern dependent on an operating mode; comparing the received synchronization pattern against the target synchronization pattern; and if the received synchronization pattern is of the target synchronization pattern, processing the payload; otherwise, discarding the burst.

Abstract: A mobile subscriber unit (102) transmits a signal including vocoder voices frames to a base unit (104) within a communication system (100). The base unit (104) repeats the signal including error information from the voice frames to one or more final recipient unit(s). The originating subscriber unit (102) listens to these error mitigated repeated frames and compares the received signal having error information to voice frame conditions, such as calculated, delayed and muted signal patterns. Based on the comparison, the subscriber unit (102) adjusts its power accordingly.

Abstract: In a wireless communication system with an air interface comprising a plurality of bursts, a plurality of bursts is defined. Each burst comprises a field (300) embedded within the burst. The field is one of a synchronization field (300?) and a signaling field (300?). When the field is a synchronization field, a position of at least one subsequent burst comprising the signaling field is defined, and a position of at least one subsequent burst comprising the synchronization field is defined.

Abstract: A received synchronization pattern is compared against first and second known synchronization patterns. If the received pattern is of the first known pattern, the payload is processed as voice; and if the received pattern is of the second known pattern, the payload is processed as non-voice. In an alternative, the received pattern is compared against first and second known synchronization patterns. If the received pattern is of the first known pattern, a first operating mode is selected, and if the received pattern is of the second known pattern, a second operating mode is selected.

Abstract: A received synchronization pattern (300″) is compared against first and second known synchronization patterns. If the received pattern is substantially similar to the first known pattern, the payload is processed as voice; and if the received pattern is substantially similar to the second known pattern, the payload is processed as non-voice. Alternatively, a target synchronization pattern dependent on an operating mode is selected. The received pattern is compared against the target pattern. If the received pattern is substantially similar to the target pattern, the payload is processed; otherwise, the burst is discarded. In yet another alternative, the received pattern is compared against first and second known synchronization patterns having a common length. If the received pattern is substantially similar to the first known pattern, a first operating mode is selected, and if the received pattern is substantially similar to the second known pattern, a second operating mode is selected.

Abstract: In a wireless communication system with an air interface comprising a plurality of bursts, a plurality of bursts is defined. Each burst comprises a field (300) embedded within the burst. The field is one of a synchronization field (300′) and a signaling field (300″). When the field is a synchronization field, a position of at least one subsequent burst comprising the signaling field is defined, and a position of at least one subsequent burst comprising the synchronization field is defined.

Abstract: A phase demodulator (101) is used for sensing the phase.sub.-- angle of a phasor represented by the I and Q signals by first producing the analog I and Q signals in a direct conversion receiver (104). A phase generator (106) is used to approximate the angle of the phasor as represented by the I and Q signals by scaling and comparing the magnitudes of the I and Q signals and making decisions based on their relative magnitudes. The scaling includes successive alteration of the magnitude of the I and Q signals.sub.-- depending on their relative magnitudes. A DSP (108) is used to receive this bit stream representation (302) of the phasor and recover the information signal.

Abstract: A digitally modulated signal is conditioned, such as to facilitate amplification. The digitally modulated signal is derived from an information stream which is mapped onto a symbol constellation to generate a sequence of channel symbols. The sequence of channel symbols is processed to provide a conditioned signal having a signal envelope that avoids signal envelope magnitudes below a threshold value (500). From a signal envelope representing the sequence of channel symbols, symbol interval minimum values are determined as the signal envelope transitions through successive channel symbols of the sequence (510). The conditioned signal is generated by localized adjustment of the signal envelope, such as by insertion of an adjustment pulse, to increase a particular symbol interval minimum value, when that value is below the threshold value (520, 530, 540, 545, 555).

Abstract: An electronic device (100) includes a regulator (102) for generating an operating voltage. The device (100) also includes at least one component (110) using the operating voltage and requiring a minimum input voltage for proper operation. The device (100) further includes a sensor (115) for sensing the minimum input voltage of the component (110) to produce a minimum operating voltage. Also included in the device (100) is a feedback circuit (116), responsive to the sensor (115), for feeding the minimum operating voltage to the regulator (102) whereby the regulator (102) alters the output voltage to the level of the minimum operating voltage.

Abstract: In a system for transmitting digital information, transmitter operating parameters (503) are transmitted with other communication message information (501, 505, 507, 509, 511, 513, 515, and 517) to aid communications.

Abstract: Pulsewidth-modulated amplifier (100) includes a controller (102) which provides for a set of compensated signals (114, 158 and 160). The compensated signals are used for driving a speaker (136). Controller (100) includes a storage area for storing distortion characteristics for the amplifier for a predetermined operational frequency range. The compensated drive signals (114, 158 and 160) help compensate for the electrical non-linear distortions that occur in amplifier (100) and thereby help reduce the output distortion of amplifier (100).

Abstract: An amplifier (1) used with a pulse width modulated signal which improves the efficiency of a low level input signal comprises two or more switching devices (7,9) with common source/drain or emitter/collector connections. The gates or the bases of the devices are independently driven to optimize the efficiency of the various Rds (on) resistance values of the transistors (61, 63, 65, 89, 91, 93) used in the devices. The amplifier is operated so that during the highest output levels, select switching devices (61, 63, 65) are utilized to reduce in series resistance with the load (13). As output power decreases, devices (89, 91, 93) with higher Rds (on) resistance values are activated by a control signal which greatly improves DC to DC conversion efficiency with improved output voltage resolution, dynamic range and reduced electromagnetic interference potential.

Abstract: An audio amplifier (100) switches between a pulsewidth-modulated (PWM) mode to an analog mode when required in order to reduce unwanted EMI when the signals being reproduced fall within a predetermined threshold range such as when reproducing low amplitude signals. Amplifier (100) includes both a pulsewidth-modulator (114) and a low-level analog amplifier (126) coupled to a speaker bridge circuit. When controller (106) determines that the input signal (102) is at a predetermined level, controller (106) selectively applies to the load (164) an analog signal instead of the PWM signal, this provides for improved dynamic range and reduced amplifier produced EMI.

Abstract: The communication device (100) operates in full duplex mode by allowing its transmitter (106) to periodically interrupt transmission to allow for a second communication device (702) to send its request-to-transmit signal. This signal is received by the receiver (108) and coupled to a controller (110). The controller (110) dynamically reduces the rate at which it codes the voice in response to the activity on the channel. The coded signal is then coupled to the transmitter (108) for transmission. A sync and control header is included at the beginning of each transmission to allow the two communication devices (100 and 702) to remain in sync and to be aware of the coding rate each of the communication devices (100 and 702) has employed in its most recent transmission.

Abstract: Power consumption in a portable communication unit (101) is reduced by first transmitting at a first time, a message (701) at a first transmit power level to a repeater (103) on a first communication channel. At a second time the message (701) is repeated (903) by the repeater on a second communication channel, thereby transmitting a delayed message (703). The portable communication unit (101) tunes (807) to the second communication channel after transmitting all of the message (701), so as to receive at least part of the delayed message (703). The repeater (103) establishes a receive quality metric (705) for the message (701) and transmits (909) the receive quality metric after all of the delayed message (703) is transmitted. The portable communication unit receives and stores (809) the receive quality metric (705), and determines a second transmit power level for transmitting another message using the receive quality metric.

Abstract: A battery package (100) includes a transparent window (108) which communicates information about the battery to a battery-powered device such as a portable radio (200). Information about the battery (100) is communicated through the window (108) by a series of light pulses, and is received by a light sensor (340) in the radio. The information is processed by the radio microprocessor (344) and the status of the battery (100) is displayed on the radio display (346). The window (108) is gas permeable and water impermeable, serves as a vent for the battery housing (110) and also as an optical data transmission window.

Abstract: A tone generator for producing a plurality of output tone waveforms for a plurality of frequencies, includes an encoder for selectively generating a first waveform that has a first number of states and second waveform that has a second number of states which are less than the first number of states. A control circuit is connected to the encoder and selects the second waveform for higher frequency output tones and the first waveform for lower frequency output tones. The control circuit provides a control clock signal to the encoder for determining the frequency of the output tones. A low pass filter is connected to the encoder for filtering the output tones. The encoder includes a plurality of flip flips having outputs connected to a summer by gates that are actuated by the control circuit.

Abstract: A decoder circuit is provided which employs digital sampling and correlation apparatus to detect the presence of a received tone signal exhibiting a predetermined frequency. Samples of received tone signals are taken and, in effect, multiplied by a substantially rectangular observation window which includes a bite interval of selected duration and location therein. A correlator correlates the windowed samples to detect samples corresponding to the predetermined frequency (main lobe frequency). A significant decrease in undesired side lobe response is thus achieved.

Abstract: In a transceiver, a multiple function switch decoder includes means for detecting actuation of the switch and means for monitoring the status of the receiver. A timer responsive to the monitoring means and detecting means establishes a predetermined time interval following each switch actuation or each received message of predetermined type. When the switch is actuated during the time interval the transmitter is enabled. When the switch is activated outside the time interval the receiver audio is activated so the user may monitor the channel. During the first switch actuation in any given time interval an encoder is enabled. On subsequent switch actuations during the same time interval the encoder is inhibited. This allows a single switch to perform a plurality of transmitter and receiver functions.

Abstract: The accuracy of a required tone set, digitally synthesized by a microprocessor, is improved beyond the theoretical limit of the microprocessor circuitry by producing each tone at a frequency which is a sub-multiple of the desired frequency, then multiplying to provide the desired frequency. With the addition of a multiplier such as a doubler, a better choice of oscillator frequency becomes possible which further increases the tone frequency accuracy. The microprocessor can also reduce the start up time and the time between tones, eliminating delays in transmitting a series of coded tones.