Method and system are disclosed for automated calibration of the VCO gain in phase modulators. The method and system of the invention comprises synthesizing, in a phase modulator, a signal having a given output frequency using a controlled oscillator having a frequency control input, a modulation input, and a feedback loop. A frequency control signal is applied to the frequency control input, and gain variation of the controlled oscillator is compensated for outside of the feedback loop via the modulation input. The method and system of the invention may be employed in any telecommunication system that uses phase and amplitude modulation, including EDGE and WCDMA systems.

Trimming of a two point phase modulator

A voltage-controlled oscillator having an inductor circuit, n pieces (n is two or more) of variable capacitance circuit having variable capacitance elements, negative resistance circuits, and reference voltage generation means of generating a reference voltage from a power supply voltage, and wherein a predetermined reference voltage is inputted to some terminals of the variable capacitance elements of the n pieces of variable capacitance circuit, a control voltage is inputted to the other terminals thereof, and of the variable capacitance elements of the n pieces of variable capacitance circuits, the predetermined reference voltage inputted to some terminals of the variable capacitance elements of at least two pieces of the variable capacitance circuit is different.

Voltage-controlled oscillator, radio communication apparatus and voltage-controlled oscillation method

A digitally controlled oscillator provides high resolution in frequency tuning by using a digitally controlled capacitive network that includes a tunable capacitive circuit, a first capacitor and a second capacitor. The tunable capacitive circuit generates a variable capacitance according to a digital control word. The first capacitor is coupled in an electrically parallel configuration with the tunable capacitive circuit. The second capacitor is coupled in an electrically serial configuration with a combination of the first capacitor and the tunable capacitive circuit. The first capacitor and the second capacitor are sized such that an effective capacitance of the digitally controlled capacitor network has a step size that is a fraction of a step size of the variable capacitance in response to an incremental change in the digital control word.

High-resolution digitally controlled oscillator and method thereof

There is provided a VCO having a modulation function capable of easily constituting a correction circuit which can obtain a predetermined modulation degree even when element irregularities are present. A modulation current terminal is connected to an anode side connection point of a first and a second varactor diode. A first resistor is connected between the connection point and an anode side connection point (grounding voltage) of a third and a fourth varactor diode. Voltage deciding the oscillation frequency is input from the voltage input terminal via the second resistor to the cathode side connection point of the first and the third varactor diode and via the third resistor to the cathode side connection point of the second and the fourth varactor diode. A first and a second capacitor are connected from a power source via a first and a second inductor to the cathode side of the first and the second varactor diode. Thus, it is possible to obtain a circuit having a frequency modulation degree expressed as a function of Kv.

Voltage control oscillator having modulation function

Voltage-controlled oscillator, radio communication apparatus and voltage-controlled oscillation method for reducing degradation of phase noise characteristic

A voltage-controlled oscillator for frequency modulation includes an oscillator core with a tunable resonant circuit component which is driven with a control voltage. Furthermore, a modulator component is provided which is driven with a modulation signal for frequency modulation. The modulator component is additionally coupled to the terminal for supplying the control voltage. As a result, a constant modulation deviation can be achieved over the entire tuning range even in the case of oscillators having a large tuning range. The oscillator circuit is particularly suitable for use in transmitting circuits for digital communication.

Voltage-controlled oscillator for frequency modulation

Es ist ein spannungsgesteuerter Ozillator zur Frequenzmodulation vorgeschlagen, aufweisend einen Oszillatorkern (1) mit einem abstimmbaren Resonanzkreis-Bauelement (3), welches mit einer Steuerspannung (A) angesteuert wird. Weiterhin ist ein Modulator-Bauelement (4) vorgesehen, welches fur eine Frequenzmodulation mit einem Modulationssignal (B) angesteuert wird. Das Modulator-Bauelement (4) ist zusatzlich mit dem Anschlus zur Zufuhrung der Steuerspannung (A) gekoppelt. Hierdurch kann auch bei Oszillatoren mit einem grosen Abstimmbereich ein konstanter Modulationshub uber den gesamten Abstimmbereich hinweg erzielt sein. Die vorliegende Oszillatorschaltung ist besonders zur Anwendung in Sendeschaltungen der digitalen Kommunikation geeignet.

Faramarz Rassouli

Papers

Voltage-controlled oscillator for frequency modulation

Spannungsgesteuerter Oszillator zur Frequenzmodulation