Automatic attenuation of analog-digital-converter (adc) input signal based on error vector magnitude (evm) performance

A method comprising:

• receiving a radio frequency (RF) input signal at an input of an RF test device;
• attenuating, by an RF attenuator of the RF test device, the RF input signal by an RF attenuation value into an RF attenuated signal;
• down-converting, by a down-converter of the RF test device, the RF attenuated signal into a down-converted signal;
• digitizing, by an analog-digital converter (ADC) of the RF test device, the down-converted signal into a digitized signal, wherein the digitized signal is utilized as a measurement signal of the RF input signal;
• demodulating, by a demodulator of the RF test device, the measurement signal to recover the RF input signal;
• mapping, by a mapping unit of the RF test device, the recovered RF input signal to in-phase (I) and quadrature (Q) vectors to generate a reference signal;
• comparing, by a comparator of the RF test device, the measurement signal and the reference signal to generate error vectors;
• and
• adjusting, by a processor of the RF test device, the RF attenuation value for the RF attenuator based on the error vectors.

A test device to analyze a radio frequency (RF) input signal, comprising:

• a digitization subsystem comprising:
• an RF attenuator to attenuate the RF input signal by an RF attenuation value into an attenuated signal,
• a down-converter to down-convert the attenuated signal into a down-converted signal, and
• an analog-digital converter (ADC) to digitize the down-converted signal into a digitized signal, wherein the digitized signal is utilized as a measurement signal of the RF input signal;
• an error vector magnitude analysis subsystem comprising:
• a demodulator to demodulate the measurement signal to recover the RF input signal,
• a mapping unit to map the recovered RF input signal to in-phase (I) and quadrature (Q) vectors to generate a reference signal, and
• a comparator to compare the measurement signal and the reference signal to generate error vectors;
• a processor to adjust the RF attenuation value for the RF attenuator based on the error vectors;
• and
• a field programmable gate array (FPGA) to process the digitized signal from the ADC and send the processed digitized signal to operational circuits for displaying or storing the processed digitized signal.