Printer FriendlyEmail Article Link

GNSS Positioning Simulator: Should I expect to see exactly the same spectrum for image rejection as shown in the calibration procedure?

  • STR4730 / 4750 / 4760 / 4780 / 4790
  • GSS7700 / 7735 / 7790 / 7800 / 7900
  • GSS8000
  • It is very unlikely that you'll get a spectrum on the analyser that looks exactly like the example figure for image rejection shown in the Customer Calibration Procedure document
  • Indeed that figure is somewhat exaggerated to make it more obvious where those three main signals might appear in relation to one another
  • In most cases you'll find that only the wanted signal is immediately clear and that the carrier or image are not present above the analyser noisefloor at all (see Note)
    • Which is the ideal case


  1. This is based on the typical analyser settings most commonly used for the image rejection part of the calibration procedure:-
        - Attenuation = 0dB
        - Reference Level = -40dBm (adjust this as necessary)
        - Centre Freq = in accordance with values given in calibration procedure
        - Span = 200kHz
        - Res BW = 300Hz (adjusted to give the lowest possible noisefloor without the sweep taking a long time, e.g. sweep < 5s)

Product : Calibration,STR4790,STR4780,STR4760,STR4750,STR4730,GSS7790,GSS7735,GSS7700,GSS7800