Lucent Technologies Inc.

Gerhard Kaminski

Georg Fischer

Wolfgang Franz Eckl

The present invention provides a method and an apparatus for controlling a Q-factor for a filter. The method comprises stabilizing an active feedback to provide a variable feedback in a filter, varying the active feedback based on an input signal to the filter, and producing a desired Q-factor for the filter at a first frequency band, in response to the variable feedback. The method further comprises reconfiguring a center frequency and a bandwidth of the filter based on a channel bandwidth of the input signal to the filter to adjust the Q-factor for the filter in response to a second frequency band different than the first frequency band. By reconfiguring a center frequency and a bandwidth of a filter, the Q-factor for the filter, such as a flexible or reconfigurable filter, may be controlled across a multiplicity of frequency band signals. Using software, for example, a common signal path may be provided for the multiplicity of frequency band signals within a frequency agile radio of a base station by tuning the radio based on a variable feedback through realization of a negative parallel resistance. Thus, tuneability of the Q-factor may provide frequency agile radios that include flexible or reconfigurable filters in a base station to serve different frequency bands without changing hardware. In this way, significant savings associated with frequency agility may be obtained.

Controlling Q-factor of filters

The invention proposes a device for high-frequency and/or radio-frequency tuning comprising within one IC-package a first variable capacitor (C) and at least one second capacitor (C), each of the at least one second capacitor (C) being fixed or variable respectively, at least one signal path connected to the first variable capacitor (C) and providing at least one input and one output port (rf-port, rf-port) and at least one controllable switching means (S) for individually connecting and disconnecting at least one of the at least one second capacitor (C) into the signal path or from the signal path, in particular in parallel to the first variable capacitor (C).

Varactor with extended tuning range

The present invention provides a method and an apparatus for selectively pretuning and updating a phase lock loop, deployed in an integrated circuit including an agile radio, such as a wideband or an ultra wideband frequency agile radio in a telecommunication system, for example, a reconfigurable multiband and/or multistandard mobile communication system. In one embodiment, a phase lock loop may comprise a digital storage having a first desired frequency. An oscillator may provide an oscillator frequency and a frequency generator circuit capable of producing at least one control signal may cause the oscillator to adapt the oscillator frequency based on the first desired frequency in response to a trigger signal. A pretune unit may apply a pretune voltage to a tuning element to cause the oscillator to calibrate the oscillator frequency to the first desired frequency. An output voltage may be added at the output of a loop filter to the pretune voltage to tune the output voltage of the loop filter such that to set the oscillator frequency substantially at the first desired frequency. An update unit may automatically determine whether one or more parameters of a phase lock loop unit have changed to dynamically update the pretune voltage.

Self-tunable phase lock loop

Apparatus for deriving an analog signal from a pulse-width modulated signal, for use in a closed-loop control system such as a phase-locked loop, is arranged to provide non-linear conversion such that the ratio of the magnitude of the analog output signal to the pulse width is greater for larger pulse widths than for smaller pulse widths. In the illustrated apparatus the output signal is derived by an integrator, gated by the pulse-width modulated signals, for integrating, during the duration of a pulse, a signal that increases with time. The increasing signal may be supplied by a positive feedback arrangement from the output of the integrator, or by a feed-forward arrangement from the output of a further gated integrator arranged to integrate a constant signal.

Pulse-width to voltage converter

The invention proposes a device for providing tunable high-frequency and/or radio-frequency comprising within one IC-package at least four signal paths providing at least two input and at least two output ports (rf-port, rf-port, rf-prot, rf-port) at least one active component (T) and at least one variable passive component (C, C) connected at least with an input port of the active component (T), and at least one control path for controllable tuning the at least one variable passive component (C, C).

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Fuerth, Germany

Gerhard Kaminski