Abstract: An amplifier having multiple gain modes comprises a plurality of cascoded input transistors connected to an input and arranged in parallel, a degeneration stage connected to the input transistors and having a variable impedance, and switching means for switching between different modes of the amplifier by switching off one or more of the input transistors and varying the impedance of the degeneration stage.

Abstract: A method of reducing d.c. offset comprises comparing the a first variable signal with a second variable signal, producing a control signal in dependence upon the comparison, providing the control signal to a charge pump for generation of a feedback signal, and varying the first signal and/or the second signal in dependence upon the feedback signal thereby reducing any difference between the d.c. level of the first signal and the d.c. level of the second signal.

Abstract: Apparatus for controlling an integrated circuit comprises a power control device for controlling the power to at least part of the integrated circuit, the power control device is connected to a first input, for receiving a power-down signal, and a second input, for receiving a power-up signal, the power control device is adapted to power-up the at least part of the integrated circuit if a power-up signal is received at the second input when the at least part of the integrated circuit is in a powered-down state, and the power control device is further adapted to maintain the at least part of the integrated circuit in the powered-up state regardless of any signal received at the second input when the at least part of the integrated circuit is in a powered-up state, the apparatus is arranged so that the second input is also connected to a component of the integrated circuit and the apparatus comprising means for sending a signal to the component of the integrated circuit via the second input when the at least pa

Abstract: An amplifier having multiple gain modes comprises a plurality of cascoded input transistors connected to an input and arranged in parallel, a degeneration stage connected to the input transistors and having a variable impedance, and switching means for switching between different modes of the amplifier by switching off one or more of the input transistors and varying the impedance of the degeneration stage.

Abstract: Apparatus for controlling an integrated circuit comprises a power control device for controlling the power to at least part of the integrated circuit, the power control device is connected to a first input, for receiving a power-down signal, and a second input, for receiving a power-up signal, the power control device is adapted to power-up the at least part of the integrated circuit if a power-up signal is received at the second input when the at least part of the integrated circuit is in a powered-down state, and the power control device is further adapted to maintain the at least part of the integrated circuit in the powered-up state regardless of any signal received at the second input when the at least part of the integrated circuit is in a powered-up state, the apparatus is arranged so that the second input is also connected to a component of the integrated circuit and the apparatus comprising means for sending a signal to the component of the integrated circuit via the second input when the at least pa

Abstract: A circuit for deriving an output clock signal from an input clock signal, the output clock signal having a frequency which is 1/Nth of the frequency of the input clock signal, where N is an odd number. The circuit comprises a plurality of latches configured as a latch ring, the latches being arranged in successive pairs, each pair of latches comprising a first latch that switches on one of the rising or falling edge of the input clock signal, and a second latch that switches on the other of the rising or falling edge of the input clock signal. An RS flip flop is coupled to receive at one of its set and reset inputs an output from the latch ring that is switched on a rising edge, and at the other of the set and reset inputs an output from the latch ring that is switched on a falling edge. Said output clock signal is provided at an output of the RS flip flop.

Abstract: Apparatus for controlling an integrated circuit comprises a power control device for controlling the power to at least part of the integrated circuit, the power control device is connected to a first input, for receiving a power-down signal, and a second input, for receiving a power-up signal, the power control device is adapted to power-up the at least part of the integrated circuit if a power-up signal is received at the second input when the at least part of the integrated circuit is in a powered-down state, and the power control device is further adapted to maintain the at least part of the integrated circuit in the powered-up state regardless of any signal received at the second input when the at least part of the integrated circuit is in a powered-up state, the apparatus is arranged so that the second input is also connected to a component of the integrated circuit and the apparatus comprising means for sending a signal to the component of the integrated circuit via the second input when the at least pa

Abstract: A frequency generation circuit comprises a crystal oscillator (10) for providing an input frequency, a phase-locked loop circuit (28), and a programmable frequency divider (42) for frequency dividing an output from the phase-locked loop circuit. The frequency generation circuit can generate a plurality of different output frequencies for supply to respective DAB and FM tuners (50, 60, 70). The frequency generation circuit can be used, together with a baseband circuit (14), in a radio receiver (1, 2). The same oscillator (10) and phase-locked loop circuit are used to drive the baseband circuit.

Abstract: A method of reducing d.c. offset comprises comparing the a first variable signal with a second variable signal, producing a control signal in dependence upon the comparison, providing the control signal to a charge pump for generation of a feedback signal, and varying the first signal and/or the second signal in dependence upon the feedback signal thereby reducing any difference between the d.c. level of the first signal and the d.c. level of the second signal.

Abstract: A circuit for deriving an output clock signal from an input clock signal, the output clock signal having a frequency which is 1/Nth of the frequency of the input clock signal, where N is an odd number. The circuit comprises a plurality of latches configured as a latch ring, the latches being arranged in successive pairs, each pair of latches comprising a first latch that switches on one of the rising or falling edge of the input clock signal, and a second latch that switches on the other of the rising or falling edge of the input clock signal. An RS flip flop is coupled to receive at one of its set and reset inputs an output from the latch ring that is switched on a rising edge, and at the other of the set and reset inputs an output from the latch ring that is switched on a falling edge. Said output clock signal is provided at an output of the RS flip flop.