Abstract: A phase detection system for providing a phase signal indicative of a phase difference between first and second input signals, with the system including a pair of amplification channels for receiving the input signals, with each channel including a plurality of amplifier stages. The outputs of the two amplification channels are connected to the inputs of a multiplier arrangement, with the arrangement producing an uncompensated phase signal. Compensation circuitry is provided to receive a magnitude signal indicative of the relative magnitudes of the two input signals, with the magnitude signal being used to produce a corrected phase signal indicative of the phase difference between the two input signals.

Abstract: Embodiments of the invention may be directed to a continuous analog phase shifter for radio frequency (RF) signals, which can be integrated on a CMOS process or another compatible process where inherent process-dependent passive components such as inductors and capacitors may have low quality factors. Insertion loss degradation for a given amount of phase shift may be compensated by using an active compensation circuit/device that smartly controls negative resistance generated from the compensation circuit/device to cancel out finite resistance of a network, leading to very small insertion loss variation. According to an example aspect of the invention, improved phase linearity and increased phase shift for a given size may be obtained by incorporating the compensation circuit/device. Thus, example analog phase shifters in accordance with example embodiments of the invention may have one or more of low insertion loss variation, small size, and good phase linearity over more than a 360 degree phase shift.

Abstract: An oscillation signal generator for compensating for an in-phase (I)/quadrature-phase (Q) mismatch and a communication system including the same are provided. The oscillation signal generator includes a first latch configured to generate an I oscillation signal, a second latch that is cross-coupled with the first latch and generates a Q oscillation signal, and a phase compensator connected to at least one of the first latch or the second latch. The phase compensator complementarily adjusts bias currents of the first and second I differential transistor pairs of the first latch and/or complementarily adjusts bias currents of the first and second Q differential transistor pairs of the second latch. Accordingly, the I/Q mismatch is compensated for without an additional device, so that the phase match between an I signal and a Q signal is improved in the communication system.

Abstract: A novel amplitude deviation correction circuit which corrects an amplitude deviation between an I signal and a Q signal is disclosed. An average amplitude deviation between an I signal amplified by a variable gain amplifier and a Q signal amplified by another variable gain amplifier is detected by an amplitude comparison circuit, and +1 volt or −1 volt is outputted in response to a result of the detection. An integration circuit integrates the output of the amplitude comparison circuit and controls the gains of the variable gain amplifiers in response to a result of the integration.

Abstract: A phase shift circuit includes a CR phase shifter for receiving an input signal to output a pair of first signals having a 90.degree. phase difference therebetween, a pair of variable-gain amplifiers for receiving the first signals to output a pair of second signals, an adder for adding both the second signals to output a sum signal, a subtracter for outputting a difference signal between the second signals, and a phase error detector for detecting the phase difference between the outputs from the adder and the subtracter to output a pair of gain control signal based on the phase difference. The gain control signal is fed-back to the variable-gain amplifier to control the ratio between the gains of the variable-gain amplifiers.

Abstract: An IQ modulator incorporates a quadrature network that is responsive to a frequency dependent control signal and that has in-phase and quadrature signals that are of equal amplitude and in exact quadrature over a wide range of applied frequencies. The quadrature network includes RC and CR phase shifters whose C's are fixed capacitors of equal value and whose R's are made equal to each other and to the capacitive reactance of the C's by the action of the frequency dependent control signal. The R's may be FET's. The frequency dependent control signal may be generated without express knowledge of the applied frequency by a servo loop that nulls out the amplitude difference between the in-phase and quadrature outputs from the quadrature network; it may also be generated from a look-up table as an express function of frequency. The frequency dependent control signal is split into separate instances that are applied to each R, and an offset may be introduced therebetween to provide extreme precision.

Abstract: A digital-to analogue converter for producing an RF output signal proportional to a digital input word of N bits from an RF reference input, N being an integer greater or equal to 2. The converter comprises a plurality of power splitters, power combiners and a plurality of mixers or RF switches connected in a predetermined configuration.