Operating Manual Vol 1 - ES Documentation

SMIQDigital Standard GSM/EDGE2.18 Digital Standard GSM/EDGEWith the options Modulation Coder (SMIQB20) and Data Generator (SMIQB11) provided, modulationsignals according to the GSM standard can be generated. GSM is a TDMA standard for cellular mobileradio 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 usedwith the older modulation coder option (SMIQB10), however in this case GSM and EDGE cannot bemixed.SMIQ can generate both the transmit signal of a base station (BS) and the transmit signal of a mobilestation (MS). Transmission from BS to MS is called "downlink", "uplink" being used for transmission inthe opposite direction.Each TDMA frame consists of 8 slots. Each slot can be switched on or off separately. Moreover, adefined 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 BurstThe 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 theselected slots. Using a digital signal processor the data generator generates a data sequence withmodulation data and control signals for envelope control.The data generator in SMIQ generates a data stream which is converted into IQ signals in themodulation coder. According to the GSM standard, the modulation type is GMSK at a symbol rate of270.833 ksymbol/s and Gauss filtering. The symbol rate can be changed in SMIQ. GFSK with adjustablefrequency deviation can be used as a modulation type, too.The modulation type for EDGE slots is 8PSK, with 3/8π rotation at a symbol rate of 270.833 ksymbols/sand linear Gauss filter.1125.5555.03 2.301E-9