Thomson Licensing

Thomson Licensing S.a.

Mehmet Ipek

Heinrich Schemmann

Sabine Roth

Martin Rieger

A variable-gain RF amplifier arrangement whose input impedance is essentially independent of the selected gain is proposed, which has a large number of selectable elementary amplifiers, with an input signal being scaled and the input impedance being set to be the same by means of switchable current limiting elements upstream of the elementary amplifiers, which are associated with the elementary amplifiers. The circuit also has a low noise level, which is largely independent of the selected gain, and good linearity. A broadcast radio receiver as well as a receiver for receiving data signals using an amplifier according to the invention are also proposed.

Controllable RF broadband and amplifier with a constant input impedance

The high frequency oscillator comprises a reference oscillator, a phase-locked loop circuit with a phase frequency detector, a charge pump, a ring oscillator and a divider, the reference oscillator being coupled to the phase frequency detector for frequency control. The ring oscillator is a symmetrical delay cell oscillator containing two amplifiers with a dual output stage for providing I/Q output signal generation. The reference oscillator works in the range of 1.25-1.5 GHz and is a Colpitts type digital controlled frequency synthesizer with an external tank circuit for providing a low phase noise, and the dividing factor of the divider is four for providing a tuned output range of 5 to 6 GHz. The phase-locked loop circuit is integrated together with the reference oscillator into an integrated circuit, using advantageously a BICMOS Silicon/Germanium process, which is well suited for RF applications.

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Villingen-Schwenningen, Germany

Mehmet Ipek