2-13
Making Mixer Measurements (Option 089 Only)
Conversion Loss Using the Frequency Offset Mode
Conversion Loss Using the Frequency Offset Mode Conversion loss is the measure of efficiency of a mixer. I t is the r a tio of side-band IF power
to RF signal power, and is usually expressed in dB. The mixer translates the incoming
signal, (RF), to a replica, (IF), displaced in frequency by the local oscillator, (LO).
Frequency translation is characterized by a loss in signal amplitude and the generation of
additional sidebands. For a given translation, two equal output signals are expected, a
lower sideband and an upper sideband.
Figure 2-10 An Example Spectrum of RF, LO, and IF Signals Present in a
Conversion Loss Measurement
The following procedure describes the R channel swept IF frequency conversion loss
measurement of a broadband component mixer with power meter calibration. For this
example, we will use the following example settings. For your measurement, you will need
to use settings specific to your measurement.
Settings Used for this Example
• LO frequency of 1 GHz (1000 MHz)
• RF start frequency of 650 MHz
• RF stop frequency of 900 MHz
• IF start frequency of 100MHz
• IF stop frequency of 350 MHz
• RF < LO
• Down convertor
TIP For ease of use, the RF frequency range needs to be the same as the network
analyzer’s frequency range limit.