Texas Instruments Corporation

Rf Magic, Inc.

Sdrf Eurl

Francesco Coppola

Biagio Bisanti

Stefano Cipriani

Gianni Puccio

Lorenzo Carpineto

Eric Duvivier

Martin Alderton

Jean-Christophe Jiguet

Rémi Artinian

Francois Marot

Vanessa Bedero

Lysiane Koechlin

Pascal Guignon

Vanessa Bodrero

Variable frequency oscillators allowing wide tuning range and low phase noise is disclosed. In an illustrative embodiment, a first transistor has a first terminal (e.g. collector) connected to a reference voltage, and a second terminal (e.g. emitter) connected to a first terminal of a first current source and to ground. The first transistor further has a third terminal connected to a first inductor and to a first capacitor connected to the emitter of the first transistor and also to a second capacitor connected to ground. A second transistor is similarly constructed. In order to achieve a variable frequency oscillation between the emitters of the two transistors, a variable tank capacitor is connected between the inductors, forming a circuit connecting in series all passive components composing the LC tank, masking most of parasitic capacitances.

Variable frequency oscillator having wide tuning range and low phase noise

Multi-loop PLL structure for generating an accurate and stable frequency over a wide range of frequencies

A tunable multiple frequency source system employing offset signal phasing includes a first frequency source, a phase delay element, and a second frequency source configured to operate concurrently with the first frequency source. The first frequency source includes an input coupled to receive a reference input signal and an output for providing a first frequency source signal. The phase delay includes an input coupled to receive the input reference signal, and an output, the phase delay element operable to apply a predefined phase delay to the input reference signal to produce a phase-delayed input signal. The second frequency source includes an input coupled to receive the phase-delayed input signal and an output for providing a second frequency source signal.

Offset signal phasing for a multiple frequency source system

A multiple frequency source system includes at least one frequency source tunable to a predefined target frequency, and at least one additional frequency source operable to generate a second signal at a frequency which is either higher or lower than the target frequency. A method for tuning the tunable frequency source to the target frequency during concurrent generation of the second signal includes (i) controlling the tunable frequency source to tune to at least one frequency point frequency lower than the target frequency, and thereafter controlling the oscillator to tune to the target frequency, when the second signal is higher in frequency than the target frequency, or (ii) controlling the tunable frequency source to tune to at least one frequency point higher than the target frequency, and thereafter controlling the tunable frequency source to tune to the target frequency, when the second signal is lower in frequency than the target frequency.

Multiple frequency source system and method of operation

A first receiver frequency reference is passively coupled to a second receiver by tapping a signal directly from the resonant element, such as a crystal, of an oscillator in the first receiver to drive the input of the second receiver. The sinusoidal signal from the resonant element is relatively free of harmonics and minimizes interference that could be caused by harmonics of a square wave signal coupling or an amplified signal. The oscillator of each receiver can be selectively enabled or disabled to allow the receiver to either generate or receive the frequency reference. This technique of coupling can be used to couple a frequency reference signal between integrated circuit receivers.

Oscillator coupling to reduce spurious signals in receiver circuits

A method for mitigating phase pulling in multiple frequency source system includes generating a first signal, the first signal referred to as an existing signal operating at an existing frequency point, the existing signal having a predefined pulling bandwidth around the existing frequency point. A request is received to generate a prospective signal at a prospective frequency point which is within the predefined pulling bandwidth of the existing signal. The prospective frequency is removed from within the predefined pulling bandwidth, and the prospective and existing signals are generated at the corresponding frequency points.

System and method for mitigating phase pulling in a multiple frequency source system

A tuning circuit uses a VCO with a trimming capacitor bank. The trimming capacitor bank is calibrated by logic to accommodate a desired frequency, f. A search renders an initial control word that is accurate within one LSB. In a first embodiment, comparisons between the desired frequency and the upper and lower frequency bounds of the VCO with the trimming capacitor bank configured by the initial control word. The control word may be increased or decreased based on the comparisons. In a second embodiment, differences between the desired frequency and the actual frequency of the VCO, with the trimming capacitor bank configured by the initial control word, are compared to a threshold. The control word may be increased or decreased based on the comparison.

High-speed, accurate trimming for electronically trimmed VCO

An electronic integrated circuit includes a first signal (A) generated by a first source block () and a second signal (B) generated by a second source block (). A variable delay circuit () detects a delay between said first and second signals in calibration mode and applies the delay to the first signal during normal operation of the circuit. A fixed delay buffer () may be used to apply a delay to the second signal to compensate for known delays associated with the variable delay circuit ().

Circuitry for reducing the skew between two signals

A voltage controlled oscillator ( ) includes an LC tank ( ) and a capacitor bank ( ). LC tank ( ) includes an inductor ( ) and a varactor ( ). The capacitive output of the varactor is controlled by a control voltage &ngr;. To electronically tune the voltage controlled oscillator, a set of capacitors ( ) in the capacitor bank ( ) are enabled by a digital control signal based on a frequency comparison with a desired frequency. Once the capacitor bank is set, the frequency can be locked at the desired frequency by the phase lock loop.

Tuning circuit having electronically trimmed VCO

A phase-lock loop (PLL) filter architecture includes a first charge pump ( ) and a second change pump ( ). The second charge pump ( ) operates in opposite phase of the first charge pump ( ) in order to take away excess charge from the loop filter capacitor(s). By using a second charge pump as described, the PLL filter does not require the use of a large capacitor and can therefore be integrated.

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Francesco Coppola