Systems and methods for removing images and spurs from measured radio frequency (RF) signals

A measurement system that removes one or both of images and spurs from a signal being measured, the measurement system comprising:

• memory;
• and
• a processor that processes a reference trace and M alternate traces to remove an image from an intended radio frequency (RF) signal, the reference trace comprising N reference trace elements, each alternate trace comprising N alternate trace elements, where M is a positive integer that is greater than or equal to one and N is a positive integer that is greater than or equal to one, the processor comprising:
• logic configured to automatically determine a threshold (TH) value;
• logic configured to obtain the reference trace by taking a first measurement of an input RF signal received at an input port of the measurement system while sweeping a local oscillator (LO) of the measurement system through a first predetermined frequency range subdivided into N frequency increments;
• logic configured to obtain the M alternate traces by taking M additional measurements of the input RF signal while sweeping the LO of the measurement system through M predetermined frequency ranges, respectively, wherein each of the M predetermined frequency ranges is subdivided into N frequency increments;
• logic configured to, for the M predetermined frequency ranges, determine a minimum alternate trace comprising N minimum alternate trace elements;
• logic configured to, for each of the N minimum alternate trace elements, calculate N qualifier trace elements by taking an absolute value of a decibel difference between the N reference trace elements and the N minimum alternate trace elements, respectively, the N qualifier trace elements comprising a qualifier trace;
• logic configured to compare each qualifier trace element to the TH value;
• logic configured to, for each comparison, when the qualifier trace element is greater than or equal to the TH value, use a minimum of the respective reference trace element and the respective minimum alternate trace element as a respective final trace element of N final trace elements that comprise a final trace, and when the respective qualifier trace element is less than the TH value, use the respective reference trace element as the respective final trace element of the N final trace elements comprising the final trace;
• and
• logic configured to cause the final trace to be displayed on a display device of the measurement system.

A non-transitory computer readable medium storing code that, when executed by a computer processor, processes a reference trace and M alternate traces to produce a final trace with one or both of images and spurs removed, the reference trace comprising N reference trace elements obtained by taking a first measurement of an input RF signal received at an input port of a measurement system while sweeping a local oscillator (LO) of the measurement system through a first predetermined frequency range subdivided into N frequency increments, each of the M alternate traces comprising N alternate trace elements, the M alternate traces being obtained by taking M additional measurements of the input RF signal while sweeping the LO of the measurement system through M predetermined frequency ranges, respectively, each of the M predetermined frequency ranges being subdivided into N frequency increments, where M and N are positive integers that are greater than or equal to one the non-transitory computer readable medium comprising:

• a first code segment for determining a threshold (TH) value;
• a second code segment for determining, for each of the M predetermined frequency ranges, a respective minimum alternate trace, each minimum alternate trace comprising N minimum alternate trace elements;
• a third code segment for calculating, for each of the N minimum alternate trace elements, a qualifier trace element that is an absolute value of a decibel difference between a respective reference trace element and a respective minimum alternate trace element;
• a fourth code segment for comparing each qualifier trace element to the TH value;
• a fifth code segment for selecting a minimum of the respective reference trace element and the respective minimum alternate trace element to be used as a respective final trace element of a final trace when the respective qualifier trace element is greater than or equal to the TH value, the final trace comprising N final trace elements;
• a sixth code segment for selecting the respective reference trace element to be used in the final trace if the respective qualifier trace element is not greater than or equal to the TH value;
• and
• a seventh code segment for causing the final trace to be displayed on a display device of the measurement system.