Signal generation for spectral measurements

A device comprising:

• a signal generator for a spectral measurement, the signal generator being configured to:
• generate a digital sigma-delta modulated signal including quantization noise,
• the digital sigma-delta modulated signal being generated by a sigma-delta modulation and using a feedback path that provides a signal to reduce a quantization error associated with modulating an input signal,
• the digital sigma-delta modulated signal being based on the signal and the input signal;
• and
• a digital output to feed the digital sigma-delta modulated signal to a probe,
• wherein a value of a parameter of the probe is determined using a spectral part of the digital sigma-delta modulated signal,
• the spectral part including a spectral region with a particular power density of the quantization noise, and
• wherein the device is configured such that the signal generator generates the digital sigma-delta modulated signal independent of a response from the probe.

A spectrum analyzer comprising:

• a signal generator to generate a digital sigma-delta modulated signal, including quantization noise, in a frequency range,
• the digital sigma-delta modulated signal being generated by a sigma-delta modulation and using a feedback path that provides a signal to reduce a quantization error associated with modulating an input signal,
• the digital sigma-delta modulated signal being based on the signal and the input signal;
• a digital output to feed the digital sigma-delta modulated signal to a probe;
• an input to receive a response signal from the probe;
• and
• a response analyzer to provide a spectral measurement of at least one property of the probe based on an analysis of at least a part of a frequency spectrum of the response signal and the digital sigma-delta modulated signal,
• wherein the at least one property is selected from a group comprising:
• a complex impedance,
• a conductivity, or
• a dielectricity.

A method comprising:

• providing a signal comprising at least partially a quantization noise of a sigma-delta modulation,
• the signal being generated using a feedback path that provides a feedback signal to reduce a quantization error associated with modulating an input signal,
• the signal being based on the feedback signal and the input signal;
• and
• providing the signal to a probe to utilize the signal as a stimulus signal in a spectral measurement of at least one frequency dependent property of the probe,
• the spectral measurement being based on an analysis of a frequency spectrum of a response signal from the probe and the stimulus signal, and
• the at least one frequency dependent property being selected from a group comprising:
• a complex impedance,
• a conductivity, or
• a dielectricity.

A spectrum analyzer comprising:

• a signal generator configured to:
• provide a stimulus signal for a spectral measurement of at least one frequency dependent property of a probe,
• the stimulus signal comprising at least partially a quantization noise of a sigma-delta modulation, and
• the stimulus signal being generated using a feedback path that provides a feedback signal to reduce a quantization error associated with modulating an input signal,
• the stimulus signal being based on the feedback signal and the input signal,
• the signal generator comprising an output configured to:
• transfer the stimulus signal to the probe;
• and
• a response analyzer configured to:
• transform a response signal received from the probe into a spectral measurement of the response signal in a frequency domain,
• wherein the stimulus signal is generated independent of the response signal received from the probe.