Patent ID: 7920032
Filing Date: 2011-04-05
Classification: H03B,H03L

Abstract:
1. An oscillator device for generating an oscillator signal, comprising: at least one first heater, a temperature sensor, signal processing means, and a voltage controlled oscillator; the temperature sensor and the at least first heater forming a thermal RC network; an output of the temperature sensor being connected to an input of the signal processing means; an output of the signal processing means being connected to an input of the voltage controlled oscillator; the oscillator device having a first feedback-loop comprising an output of the voltage controlled oscillator having a first connection to an input of the at least one first heater; the voltage controlled oscillator configured to generate an oscillator signal, the oscillator signal being provided as a switching signal for a heating drive signal to the at least one first heater over the first connection, and the signal processing means configured to provide a signal for altering a frequency of the oscillator signal; the first feedback loop configured to ensure that the oscillator device operates substantially at a fixed frequency related to an output signal from the thermal RC network, wherein the signal processing means are arranged to implement the function of a synchronous demodulator, the signal processing means comprising a linear amplifier, a chopper, and a low-pass filter element; the linear amplifier having an input being connected to the output of the temperature sensor and having an output being connected to a first input of the chopper, the chopper having an output being connected to an input of the low-pass filter element and having in the first feedback-loop a second input being connected to an output of the voltage controlled oscillator, and the low-pass filter element having an output being connected to the input of the voltage controlled oscillator, the linear amplifier arranged for amplifying in a substantially linear mode a signal from the temperature sensor to a linearly amplified signal; the chopper receiving on the first input the linearly amplified signal, and receiving on the second input, from the first feedback loop, the oscillator signal as a chopper control signal; the chopper being arranged for multiplication of the amplified signal and the chopper control signal to form a chopper signal, the chopper control signal being interpreted as having values +1 and −1; the chopper signal being fed to the low-pass filter element.