beautypg.com

Qpsk measurement -50 – Anritsu Series MS278XB User Manual

Page 206

background image

Modulation Measurements

Measurements

5-50

MS278XB OM

QPSK Measurement

The next class of modulation quality measurements is when you don’t have a full WCDMA transmitter,
but you want to measure the modulation quality anyway. This is a common test for RF components, for
example. These are called QPSK measurements, as you would use a QPSK-modulated signal generator
as a source.
Component measurements are similar to QAM/PSK measurements, except they are at a WCDMA chip
rate of 3.84 MHz. Signature is capable of displaying:

Vector Diagram & Constellation
Power vs. Time
EVM, Magnitude Error, Phase Error, or all 3 vs. Time
Eye Diagrams (I, Q, or both)
Optional Summary table with any diagram
EVM (RMS, Peak, Peak Location)
Magnitude & Phase Error
IQ Offset
Frequency Error

The graph types are set up using the Graph Type setup dialog shown below by pressing the button for
the measurement you want. Each tab also has a check box that is usually in the lower left corner. This is
an option to the measurement. In the dialog shown below, the option is to include a Summary table to
each of the selected graphs.

Figure 5-27. QPSK Graph Type Setup Dialog