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ET User’s Guide 3-45
Making Measurements
Measuring Conversion Loss
Measuring Conversion Loss
Conversion loss is the ratio of IF output power to RF input power
expressed in dB. This section uses an example measurement to describe
how to measure the conversion loss of a broadband mixer.
When characterizing a device's conversion loss, the analyzer uses
broadband detection to compare the transmitted signal (B*) to the
reference signal (R*). This is because the input and output signals of a
frequency-translating device may be different. Since broadband
detection measures signals at all frequencies, you may want to use a
filter to remove unwanted signals such as LO feedthrough when
performing this measurement.
For example, an RF signal at 900 MHz mixed with an LO signal at
200 MHz, results in mixing products at 700 MHz and 1100 MHz, as well
as the original 900 MHz and 200 MHz RF and LO signals.
Figure 3-21 Filtering Out the Unwanted Mixing Products