Abstract: Modulators for amplitude-modulating signals defined by phase information and envelope codes are provided with first transistors for receiving the phase information and second transistors for receiving the envelope codes. The first main electrode of one transistor is coupled to the second main electrode of the other transistor and the other second main electrode constitutes an output of the modulator. This modulator can be used in any kind of transistor environment and is simple and low cost. The doped areas of the coupled first and second main electrodes comprise an overlap to reduce cross-talk and to reduce silicon area. Polar transmitters are provided with this modulator and with a circuit for generating a phase/frequency code and the envelope code and with an oscillator for receiving the phase/frequency code and for generating the phase information. A phase shift between the phase information and the envelope code reduce aliases.

Abstract: An oscillator circuit with an oscillator device. The oscillator device has a oscillator bias contact (Vcm). A bias source (Vbias) is connected to said oscillator contact with a source contact. The voltage source includes a varying bias source which in use provides a bias varying in time. The bias source may for example be a switched DC source which in use provides an output signal varying between a first level and a second level.

Abstract: An output signal is generated for transmission in a telecommunications systems. This may involve generating an in-phase radio frequency signal by mixing an in-phase baseband signal with a first radio frequency mixer signal; and generating an alternative-phase radio frequency signal by mixing an alternative-phase baseband signal with a second radio frequency mixer signal. An output signal for transmission is generated by combining the in-phase radio frequency signal with the alternative-phase radio frequency signal, wherein the output signal has a frequency, fRF. The first and second radio frequency mixer signals are generated by generating a voltage controlled oscillator (VCO) output signal having a frequency, fVCO, such that f VCO = ( n + 1 2 ) · f RF , wherein n=1, 2, 3, . . . ; and generating one or more fractional frequency divided signals from the VCO output signal, wherein each of the one or more fractional frequency divided signals has a frequency equal to fRF.

Abstract: An equalizer circuit comprises at least one tuneable transconductance element (12, 14, 16, 18, 22) having its operating parameters determined by its supply voltage (Vdd). An automatic tuning means can be used to vary the supply voltage of the or each transconductance element.

Abstract: An equaliser circuit comprises at least one tuneable transconductance element (12, 14, 16, 18, 22) having its operating parameters determined by its supply voltage (Vdd). An automatic tuning means can be used to vary the supply voltage of the or each transconductance element.