US 2015/0177296 A1 · SPECTRUM ANALYZER USING MULTIPLE INTERMEDIATE FREQUENCIES AND MULTIPLE CLOCK CONFIGURATIONS FOR RESIDUAL, SPURIOUS AND IMAGE SIGNAL REDUCTION

Abstract

A spectrum analyzer for measuring an RF signal over a selected frequency span configured to use multiple Intermediate Frequencies (IFs) for residual, spurious and image signal reduction. The spectrum analyzer has both a primary IF path and a secondary IF path configured to provide band pass filtering of the IF signals. A master clock synthesizer is configured to reduce residual noise by providing from a single Voltage Controlled Oscillator, a master clock signal and a Local Oscillator (LO) signal. The spectrum analyzer has a microcontroller configured to change the frequency of the master clock signal and the LO signal if the center frequency of the selected span is sufficiently close to a known spurious signal.

Claims17

Dependent claims

A device for converting an RF signal over a selected frequency span comprising:

a first stage IF conversion portion comprising a local oscillator and one or more first stage mixers;
the local oscillator configured for generating a plurality of LO signals, each with an LO frequency that is different from others of the plurality of LO signals;
the one or more first stage mixers configured for sequentially converting the RF signal into a plurality of first stage IF signals, each of the first stage IF signals converted using a different one of the plurality of LO signals;
an IF filtering portion comprising a plurality of IF paths each having a filter with a filter pass band center frequency that is different from the filter pass band center frequencies of the other filters of the other of the plurality of IF paths;
a microcontroller configured for sequentially selecting, for each of the plurality of first stage IF signals, one of the plurality of IF paths to filter that first stage IF signal;
and
an IF-to-bits circuit with an ADC, the IF-to-bits circuit configured for sequentially converting plurality of first stage IF signals to a plurality of digitized IF signal sample sets.

4 more elements

A device for converting an RF signal to digital comprising:

a master Voltage Controlled Oscillator configured for generating a master VCO signal having a master VCO frequency;
an LO divider configured for generating an LO signal based on the master VCO signal using an LO divisor, the LO signal having a LO frequency with a value of the master VCO frequency divided by the LO divisor;
a clock divider configured for generating a master clock signal based on the master VCO signal using a clock divisor, the master clock signal having a master clock signal frequency with a value of the master VCO frequency divided by the clock divisor, wherein the clock divisor is different from the LO divisor;
a mixer configured for converting the RF signal to an IF signal using the LO signal;
and
an ADC further configured for converting the IF signal to a set of digitized IF signal samples using the master clock signal.

3 more elements

Dependencies are inferred from the claim text.

Spectrum analyzer using multiple intermediate frequencies and multiple clock configurations for residual, spurious and image signal reduction

Life of this patent

Spectrum analyzer using multiple intermediate frequencies and multiple clock configurations for residual, spurious and image signal reduction

Life of this patent

Abstract

Claims17