Abstract: A tunable and trimmable analog filter may include a tunable analog filter and a trimming circuit. The tunable analog filter may set the frequency of a characteristic of the tunable analog filter based on a digital tuning signal that is indicative of a desired frequency of the characteristic. However, the tunable analog filter may contain components having values that deviate from specified values due to var during manufacture of the tunable analog filter. The value deviations can cause the frequency of the characteristic not to precisely match the frequency indicated by the digital tuning signal. The trimming circuit may include a non-volatile memory that contains data. The trimming circuit may receive tuning information indicative of a desired frequency for the characteristic of the tunable analog filter.

Abstract: A tunable and trimmable analog filter may include a tunable analog filter and a trimming circuit. The tunable analog filter may set the frequency of a characteristic of the tunable analog filter based on a digital tuning signal that is indicative of a desired frequency of the characteristic. However, the tunable analog filter may contain components having values that deviate from specified values due to variations during manufacture of the tunable analog filter. The value deviations can cause the frequency of the characteristic not to precisely match the frequency indicated by the digital tuning signal. The trimming circuit may include a non-volatile memory that contains data. The trimming circuit may receive tuning information indicative of a desired frequency for the characteristic of the tunable analog filter.

Abstract: Circuits and methods for a low voltage pre-distortion circuits that provide a temperature and logarithmically compensated voltage such that a gain change of a variable gain amplifier is linear in dB and has a reduced temperature dependency. A temperature compensation circuit multiplies the transfer function of gain of the amplifier versus gain control voltage by absolute temperature. A logarithmic compensation circuit removes the non-logarithmic factor of a “1” in the denominator of the transfer function.

Abstract: Circuits and methods for providing a variable gain while powered from a low-voltage supply. In a specific embodiment, an input signal is converted to a current by an emitter-degenerated pair. A portion of the input current is discarded, while the remainder is variably steered between a shunt stage or an AC ground such as VCC. The output of the shunt stage is buffered by a high speed output, the bandwidth of which is increased by feed-forward capacitors. This arrangement may be optionally repeated for additional gain.

Abstract: A Time Division Multiple Access (TDMA) radio communication device is arranged for receiving radio signalling and information data in receive time slots. The radio communication device includes receiver circuitry for the filtering of received radio signals using a filter. The filter includes a tunable filter part and a tunable oscillator or resonator part, operatively connected such that control signals operative for the tuning of the oscillator part are also operative for the tuning of the filter part. A detector for the detection of the oscillator operation, a reference source and a comparator are arranged to provide the tuning control signals for the oscillator to operate in accordance with the reference source. The filter includes storage for storing the tuning control signals if said filter is made inoperative and for starting up the filter by using the stored tuning control signals.