HP 8753E manual Conversion Compression Using the Frequency Offset Mode

Conversion Compression Using the Frequency Offset Mode

Conversion compression is a measure of the maximum RF input signal level, where the mixer provides linear operation. The conversion loss is the ratio of the IF output level to the RF input level. This value remains constant over a specified input power range. When the input power level exceeds a certain maximum, the constant ratio between IF and RF power levels will begin to change. The point at which the ratio has decreased 1 dR is called the 1 dB compression point. See Figure 3-19.

Input Signal (RF) Input Signal (RF)

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Figure 3-19.

Conversion Loss and Output Power as a Function of Input Power Level Example

Notice that the IF output power increases linearly with the increasing RF signal, until mixer compression begins and the mixer saturates.

The following example uses a ratio of mixer output to input power and a marker search function to locate a mixer’s 1 dR compression point.

1. Set the Lo source to the desired CW frequency and power level.

CW frequency = 600 MHz Power = 13 dl3m

2.Initialize the analyzer by pressing B.

3.To set the desired CW frequency and power sweep range, press:

4. Make the connections, as shown in Figure 3-20.

3-28 Making Mixer Measurements