摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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).
摘要:
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.
摘要:
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.