SMIQ
Digital Standard GSM/EDGE
1125.5555.03
E-9
2.301
2.18
Digital Standard GSM/EDGE
With the options Modulation Coder (SMIQB20) and Data Generator (SMIQB11) provided, modulation
signals according to the GSM standard can be generated. GSM is a TDMA standard for cellular mobile
radio networks used worldwide. SMIQ is suitable for use as a signal generator for all GSM types.
With option SMIQB20, the use of GSM and EDGE slots is not limited. GSM/EDGE may also be used
with the older modulation coder option (SMIQB10), however in this case GSM and EDGE cannot be
mixed.
SMIQ can generate both the transmit signal of a base station (BS) and the transmit signal of a mobile
station (MS). Transmission from BS to MS is called "downlink", "uplink" being used for transmission in
the opposite direction.
Each TDMA frame consists of 8 slots. Each slot can be switched on or off separately. Moreover, a
defined intermediate level can be set.
A burst type has to be defined to configure a slot. The following burst types can be selected:
•
NORM
the so-called "normal burst",
•
DUMMY
burst type with a defined data pattern according to GSM standard and
•
ALL_DATA
burst type for test purposes with freely programmable data contents.
•
EDGE
the so-called EDGE Normal Burst
The following internal modulation sources are available:
•
different PRBS generators with a sequence length between 2
9
-1 and 2
23
-1 and
•
data lists, i.e. freely programmable data sequences from the data generator memory.
For generating the GSM signals, SMIQ inserts the modulation data continuously (in real time) into the
selected slots. Using a digital signal processor the data generator generates a data sequence with
modulation data and control signals for envelope control.
The data generator in SMIQ generates a data stream which is converted into IQ signals in the
modulation coder. According to the GSM standard, the modulation type is GMSK at a symbol rate of
270.833 ksymbol/s and Gauss filtering. The symbol rate can be changed in SMIQ. GFSK with adjustable
frequency deviation can be used as a modulation type, too.
The modulation type for EDGE slots is 8PSK, with 3/8
π
rotation at a symbol rate of 270.833 ksymbols/s
and linear Gauss filter.
