Operating Manual Vol 1 - ES Documentation

Digital Standard NADCSMIQ2.16 Digital Standard NADCWith the options Modulation Coder (SMIQB20) and Data Generator (SMIQB11) provided, modulationsignals according to the American NADC standard (IS-54 1 or IS-136) can be generated. NADC is aTDMA standard for cellular mobile radio networks.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 6 slots. The 6 slots can be configured for both full rate and half ratemode. For half rate, the data content for each of the 6 slots can be defined separately by means of aslot editor whereas in the full rate mode 2 slots for example slot 1 and 4 are combined in a frame. Thesettings for the first slot are then automatically used for the assigned second slot. Each slot can beswitched on or off. Moreover, a defined intermediate level can be set for uplink slots.A burst type has to be defined to configure a slot. The following burst types can be selected:• TCH a traffic channel burst with a different structure for uplink and downlink,• SHORT the so-called "shortened burst" only available during uplink and,• ALL_DATA burst type for test purposes with freely programmable data contents in the selectedslot.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, ie freely programmable data sequences from the data generator memory.For generating the NADC 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 NADC standard, the modulation type is π/4 DQPSK at a symbol rateof 24.3 ksymbol/s and √COS filtering. Symbol rate and filtering can be changed in SMIQ.1 Personal Handy Phone System ARIB Standard (RCR STD-28)1125.5555.03 2.262E-9