Abstract: A bias circuit for a transistor amplifier, the bias circuit comprising a low-pass filter block, a reference transistor, a sum node, a reference current source, and a current difference block, wherein the low-pass filter block is configured to sense a DC bias voltage at a control terminal of the transistor amplifier and provide the DC bias voltage to a control terminal of the reference transistor; the reference transistor is configured to output a bias current in response to the DC bias voltage and provide the bias current to the sum node; the sum node is configured to receive a reference current from the reference current source and combine the reference current with the bias current from the reference transistor to provide a difference current; and the current difference block is configured to receive the difference current from the sum node and provide the difference current to the control terminal of the transistor amplifier.

Abstract: A bias circuit for a transistor amplifier, the bias circuit comprising a low-pass filter block, a reference transistor, a sum node, a reference current source, and a current difference block, wherein the low-pass filter block is configured to sense a DC bias voltage at a control terminal of the transistor amplifier and provide the DC bias voltage to a control terminal of the reference transistor; the reference transistor is configured to output a bias current in response to the DC bias voltage and provide the bias current to the sum node; the sum node is configured to receive a reference current from the reference current source and combine the reference current with the bias current from the reference transistor to provide a difference current; and the current difference block is configured to receive the difference current from the sum node and provide the difference current to the control terminal of the transistor amplifier.

Abstract: A method for applying a modulation signal to a phase locked loop comprises filtering the modulation signal to provide a low frequency component and a high frequency for application to respectively the feedback and feedforward paths of a phase locked loop. The high frequency component is scaled by a gain factor before being applied to the feedforward path. The low frequency component is also scaled by a gain factor and applied to the feedforward path. The energy in a common low frequency range of the modulation signal and of the loop error signal is estimated, and the gain factors are modified dependent on the measured energy.

Abstract: The system and method of the present invention provide a single mixer (200-400) with significantly reduced noise performance at a low cost by adding a current control circuit (109) that reduces the current in at least the switching stage (103, 303, 403) during polarity changes of the local oscillator (LO) signal (104). Alternative embodiments (300-400) are provided for a single mixer having significantly reduced noise wherein the low-noise characteristic is enhanced by a further modification to the switching stage (303-403).

Abstract: The invention relates to normalisation of a TDC system (20). The TDC system (20) comprises a TDC core (21), a gain normalization circuit (22) and an adjuster (23). The TDC core (21) comprises a set of nominally identical delay elements and converts the time difference between the edges of a reference clock signal (FREF) and a controllable clock signal (CLK) into a raw TDC output code as a digital word. The adjuster (23) is configured to carry out the gain normalisation by adjusting the output code. The gain normalization circuit (22) comprises at least a processor for analyzing the occurrence probability of the output code values, and for determining the adjustment to be made by the adjuster (23) according to said occurrence probability.

Abstract: A conversion device (CD) is dedicated to conversion of baseband analog I/Q input signals into RF signals in a transmitting path of a wireless communication equipment.

Abstract: A frequency synthesiser (100) has a first variable frequency oscillator (10) for generating a first oscillator signal having a frequency responsive to a first control signal, a second variable frequency oscillator (50) for generating a second oscillator signal having a frequency responsive to a second control signal, and a phase reference generator (40) for generating a phase reference signal. There is a phase difference generator (30) for generating a phase difference signal indicative of the phase difference between the sum of the phases of the first and second oscillator signals and the phase of the phase reference signal. A controller (60) responsive to the phase difference signal generates the first and second control signals.

Abstract: A method for applying a modulation signal to a phase locked loop comprises filtering the modulation signal to provide a low frequency component and a high frequency for application to respectively the feedback and feedforward paths of a phase locked loop. The high frequency component is scaled by a gain factor before being applied to the feedforward path. The low frequency component is also scaled by a gain factor and applied to the feedforward path. The energy in a common low frequency range of the modulation signal and of the loop error signal is estimated, and the gain factors are modified dependent on the measured energy.

Abstract: This circuit includes an output stage consisting of a current source SCE 52 and a current sink SNK 51 having an identical construction. A reference signal is applied to a D-type flipflop 40A and a local oscillator signal is applied to another flipflop 40B of the same type. The output 28 (27) of the flipflop 40A (40B) triggers a control circuit 30A (30B) whose output C-SCE (C-SNK) controls the current source SCE (SNK). The inputs of a logic gate 60 are connected to the control circuits 30A, 30B, and the gate supplies an inactive state reset signal to the flipflops 40A and 40B and the control circuits 30. Bias voltages which are common for the control circuits are generated by a circuit 20 which also fixes the elementary output current of the charge pump.