Chapter 4 101
CDMA Measurements - Screens and Control Fields
Gen Dir Gen Mode
Gen Dir
This field sets the link direction of the CDMA signal.
• Fwd (forward) sets the CDMA generator to produce QPSK
modulation to imitate a base station. The EQ Filter field is
automatically set to EQ In
to apply an equalizing filter to the I and
Q paths as part of the baseband filtering, but it can be changed to
Out
.
• Rev (reverse) sets the CDMA generator to produce OQPSK
modulation to imitate a mobile station. The EQ Filter field is
automatically set to Out
(and cannot be changed) to remove the
equalizing filter from the I and Q paths.
Screens on which this field is present
CDMA GENERATOR
Gen Mode
This field selects the type of modulation information sent to the CDMA
generator’s IQ modulator.
• Data allows data to be transmitted to simulate a traffic channel with
no additive noise. (See the"Data Source" field on page 99.)
• Eb/No causes a combination of data and White Gaussian Noise
(AWGN) noise to be transmitted. The value entered is the ratio
between the energy of each information bit (E
b
) and the noise
spectral density (N
o
), expressed in dB.
• Noise causes a signal modulated by White Gaussian Noise to be
generated. The noise is band limited to 2 MHz and white inside a
1.25 MHz bandwidth centered around the RF Gen Freq. This
selection removes the Data Source, Start Frame, and # of
Frames fields from the screen; those fields are only used with the
Data and Eb/No entries.
Screens on which this field is present
CDMA GENERATOR
