摘要:
A monolithic RF amplifier circuit (10) suitable for use in the 0.8-2 GHz frequency range comprises, on-chip (12'), a gateable oscillator (24) running at about 2-5 times the amplifier input frequency or higher, coupled to a rectifier (30) and a low pass filter (34) for producing a DC signal which is fed via a bias/gain control circuit (46) to a bias / gain inputs (56, 58) of one or more amplification stages (60, 62) (e.g. GaAs FET) to provide bias therefore to ensure safe operation, and a priority control circuit (42) responsive to the bias. The priority control circuit (42) operates a power switch (18) that couples the amplification stages (60, 62) to a power supply, only when bias is present on their bias/gain inputs (56, 58) This protects the amplification stages (60, 62) against overcurrent operation. A separate external port (68) to the bias / gain control circuit (46) adjusts the magnitude of the bias to permit amplifier gain and power output to be adjusted. By gating the oscillator ON and OFF, high speed burst mode operation of the amplifier is achieved.
摘要:
A direct modulation multi-accumulator fractional-N frequency synthesiser (1) for generating a carrier signal (150) modulated by a modulation signal (170), (121), the frequency synthesiser comprising a Voltage Controlled Oscillator, VCO (10), having a tuning port for controlling the frequency of the signal (110) output by the VCO, a variable divider (20) and a multi-accumulator frequency generator (21) for controlling the variable divider, a reference signal generator (50), a phase detector (30) and a low pass filter (40), these elements being arranged to form a Phase Locked Loop arrangement, the directly modulated output signal of which is taken from the output of the VCO, wherein in-band modulation is performed by varying the variable divider and out-of-band modulation is performed by directly applying the modulating signal to the VCO tuning port.
摘要:
A sequence generator and applier (90) for applying a sequence to a frequency divider (5) forming part of a frequency synthesiser (50), the sequence generator and applier (90) including generating means (120) for generating a sequence associated with one or more frequencies to be synthesised by the frequency synthesiser, storage means (100) for storing the sequence once generated and application means (100) for applying the sequence from the storage means (100) to the frequency divider (5).
摘要:
A communications system (5) has a network (10) arranged for communication with portable communications devices (100, 200), and is further arranged for providing at least one parameter for transmission to the portable communications devices. A portable communication device is arranged for communicating with the network and is further arranged to receive the parameter, the parameter containing an indication of required dynamic spectral splattering characteristics of output power of the transmitter of the device.