China Electronics Technology Instruments AV3672 Series, User Manual

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Appendix
Appendix 6 Mixer Measurement
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the main sound signal will be measured, and the parameter name is ended with the “Main” marker; otherwise,
the order number should be added behind the parameter name.
 Measurement can be done at the input end or output end. If the input end is selected, add “In” behind the
parameter name, such as PwrMainIn. If the output end is measured, there is no additional marker behind the
parameter name, such as PwrMain. The input end is tested with the reference receiver, and the output end is
tested with the measurement receiver.
7.3.4 Simple Intermodulation Distortion Calibration
7.3.4.1 Overview
1. The source power calibration and receiver calibration interface is used in simple intermodulation
distortion calibration.
2. The intermodulation sound order can be selected in calibration.
3. Port 1 is connected to the power meter to calibrate the reference receiver and measurement receiver.

The source and receiver frequency can be calculated with the vector network analyzer, including main signals
and all intermodulation signals.

Port 1 is connected to the power meter. The reference receiver R1 can be calibrated in source and receiver
calibration.

The reference receiver R1 is used to calibrate the main signal source. At first, calibrate the low-frequency
power of Source 1 and then calibrate the high-frequency power of Source 2. Source 1 and 2 should be
disconnected to ensure impedance matching.

Directly connect Port 1 and 2 and correct Receiver B by means of calibration.
Attention
If the main sound signals frequency changes, calibration may fail.
Changes of the main sound signal frequency may result in failure of calibration. The state change may occur to the
start/stop/center frequency, frequency span, sweep point number, sweep type, etc.
7.3.4.2 Selection of Product Signal

Maximum calibration order : select the intermodulation product which can be measured (5 orders at
most). Low-frequency and high-frequency signal and intermodulation products of smaller odd orders can be
calibrated. For example, the main signals and high-order and low-order products (such as 3-order and 5-order
products) can be calibrated in 5-order intermodulation measurement.

Include 2-order calibration : calibrate 2-order products, the frequency of which is always subject to
large deviation from the main signal frequency.
Fig. 7.9 Intermodulation Distortion Calibration Process

Power Level : execute the power calibration value of Port 1. As the standard calibration power of the power
meter is 0dBm, 0dBm is generally selected as the power of source power calibration. If one component is
added between the source and calibration reference plane, the calibration power should be adjusted to keep the
power of the calibration port of the power meter at 0dBm.
The pages of other calibration steps are the same as those of source calibration and receiver calibration, so they are
not detailed here.
7.3.4.3 Saving of Intermodulation Distortion Power Data of Frequency Sweep
Only the logarithmic power amplitude in intermodulation distortion measurement data of frequency sweep can be