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Real-Time I/Q Baseband Generator User’s and Programming Guide 3-49
ESG Family Signal Generators Softkey Reference
Options UN8 and 202 C
In the GSM Format
The following figure shows an example of a normal timeslot as it is
defined by the GSM format.
•
T:
shows the contents (hexadecimal zero) of the 3-bit tail field. The
text in this field is grey, indicating that you cannot change the value
for the tail bit field.
•
E:
shows the contents (PN9) of the data selection (encryption bits)
for this timeslot. The
E
softkey makes this the active function. Other
selections include PN15, fixed 4-bit patterns, fixed patterns of ones
and zeroes, user files, or external data.
•
S:
shows the value (0) of both steal bits for this timeslot. The
S
softkey makes both steal bits the active function.
•
TS:
shows the contents (hexadecimal 0970897) of the 26-bit training
sequence for this timeslot. The
TS
softkey makes this the active
function.
•
G:
guard time appears in the visual representation of the timeslot
as an 8.25-bit field. In the actual implementation, the guard time
field in timeslots 0 and 4 are 9 bits long and the remaining timeslots
contain 8 bit fields. (This implementation is documented in the GSM
format “GSM REC. 05.10 Section 5.7” as follows: “Optionally, the BS
may use a timeslot length of 157 bit periods on timeslots with TN=0
and 4, and 156 bit periods on timeslots with TN=1, 2, 3, 5, 6, 7,
rather than 156.25 bit periods on all timeslots.”) The text in this field
is grey, indicating that you cannot change the contents of the guard
time field.
Softkey Location:
Mode
>
TDMA
>
GSM
>
Data Format Pattern Framed
>
Configure Timeslots
>
Configure Normal