
408 Chapter 15
W-CDMA Uplink Digital Modulation for Receiver Test
DPCH
too high for the current slot format, this could cause over puncturing of the transport
channel data. But since the symbol rate and slot formats are linked together, a change to
one value will automatically adjust the other when required.
5. Set the bit error rate ratio.
a. Highlight the TrCH BER Cycle field.
b. Press
125 > Enter.
The value entered composes a group of data bits that can contain a specified number of
error bits, which are entered in the following steps. If you enter zero for the
TrCH BER Cycle field, this effectively terminates the error bit insertion feature.
c. Highlight the TrCH BER ErrLen field.
d. Press
10 > Enter.
This sets the number of error bits contained in the group of data bits shown in the TrCH
BER Cycle field. The value ten means that ten of the 125-bits are error bits. The error
bit positions are randomly changed to prevent them from appearing in fixed positions
and to ensure, when multiple transport channels are used, that errors can appear
across all data blocks. You can also enter zero for no error bit insertion.
The value for the TrCH BER ErrLen cannot be greater than the value for the
TrCH BER Cycle. If you enter a greater value, the ESG will disregard the entered
parameter and set the field equal to the TrCH BER Cycle field setting.
The error ratio is calculated using the following formula:
6. Press
Apply Channel Setup.
When the Apply Needed annunciator appears, press the
Apply Channel Setup softkey. The
new settings are not be applied to the signal until this softkey is pressed.
You have now changed the DPDCH symbol rate and modified the transport channel bit
error rate to 8 percent. Figure 15-40 shows the code setup display after making the
changes.
BER = TrCH BER ErrLen / TrCH BER Cycle
Using the values entered above: BER = 10 / 125
BER = .08 or 8%
The BER is shown in the grayed-out TrCH BER field. See Figure 15-40 for the location
of the BER fields.
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