Baseband Fading Simulator ABFS
Contents
1. mph lt 0 13 min gt 372 h lt 1 dB typ lt 0 3 dB lt 2 dB typ lt 0 3 dB 30 dB to 30 dB 0 1 dB l to 1 0 05 O to 12 dB 1 dB 12 109m s i So a ee to 200 M min fee paths 1 to 6 with paths 7 to 12 of a channel A or B O to 100 5 ue 360 setting of the RF results in an auto matic calculation and display of the Doppler requency according to the set motion speed 5 MHz to 8 5 GHz RF can be stored in a list and quickly set via a serial interface RS 232 1 byte with start and stop bit 8 or 16 bit as address for each fad ing channe lt 3 5 ms Noise generator with options ABFS B1 or ABFS B3 Amplitude distribution Crest factor Gaussian statistically independent for land Q 14 dB Certified Quality System ISO 9001 DQS REG NO 1954 Noise power level in relation to full scale level Range Resolution Error Output level at full scale level AC Insertion loss between input and output Output spectrum Bandwidth Frequency response up to 0 7 x system bandwidth max 5 MHz RF system bandwidth Setting range Resolution Memory for device settings Storable settings Frequency response Remote control System Command set Connector IEC IEEE bus address Interface functions General data Power supply Electromagnetic compatibility Environmental conditions Operating temperature range Storage temperature range Climatic resistance Mechanical resista2. 944 1013 9366 00 ABFS 1114 8564 94 CPDF cumulative probability distribution function Ratio between discrete and distributed component The phase differences between paths caused by different settings of path delay are taken into account when the RF is modified This applies to frequency hop ping mode only A 0 5 x system bandwidth is used for baseband Baseband Fading Simulator ABFS 5 0200 Bu we Printed in Germany PD 757 5466 21 Baseband Fading Simulator ABFS Trade names are trademarks of the owners Subject to change Data without tolerances typical values ROHDE amp SCHWARZ ROHDE amp SCHWARZ GmbH amp Co KG Muehldorfstrasse 15 81671 Munich Germany P O B 801469 81614 Munich Germany Telephone 498941 29 0 www rohde schwarz com CustomerSupport Tel 49 1805124242 Fax 4989 4129 3777 E mail CustomerSupport rsd rsd de
3. can be tested with this configuration e Coupling of two channels so that a channel with 12 propagation paths is obtained Fig 4 gives a more detailled insight how the fad ing simulator works Output LQ Channel 1 Noise generator optional fading simulator LQ Channel 2 NX Noise generator Baseband Fading Simulator ABFS 3 High versatility by options Noise Generator ABFS B1 adds a noise source to the output of the first channel see Fig 3 so that noise can be simulated in the frequency band used The noise generator can be switched on or off irrespective of the operating modes of the basic version Second Fading Simulator ABFS B2 offers two extra channels with the same characteristics in addition to the two channels of the basic model Second Noise Generator ABFS B3 rep resents an additional noise source for a further output This second noise generator is either assigned to the sec ond channel of the basic ABFS with first noise generator ABFS B1 for the first channel or to the first channel of the second fading simulator ABFS B2 Fading profiles of the Rayleigh Rician Pure Doppler Lognormal or Suzuki method can be assigned to each of the propagation paths irrespective of the selected circuit see Fig 3 In addition to the fading profiles men tioned the following parameters can be defined for each propagation path e Path attenuation e Delay time e D
4. of multiple conversion y F Fig 1 Fading of a baseband signal from AMIQ with Fading Simulator ABFS Due to this baseband fading simula tion an upgrade to new networks or standards is easy lt gt ROHDE amp SCHWARZ A TRANSFER SHORTCODE LONG_CODE HOP TRIGGER OFF EXT RS232 J HOP CONTROL 1 Ai A1782 STATE OFF ON SELECT LIST CURRENT HOP10 MENU VARIATION CALIBRATE DELETE LIST MEM SEQ FUNCTION FILL INSERT DELETE EDIT VIEW HOP CONTROLJ UTILITIES i HOP CONTROL 2 _ STATE SELECT LIST j QUICK SELECT O FADING AWGN z IX ON OFF ON OFF MADE IN GERMANY 2 2 Baseband Fading Simulator ABFS Fit for the future Baseband Fading Simulator ABFS is suitable for universal mobile radio applications in research development and production It comprises all sce narios and statistical models for simu lating sporadic fading as specified in the test regulations of mobile radio standards eg GSM S 54 US 136 or IS 95 CDMA The flexible concept of ABFS allows the simulation of radio channels of existing and future communication sys tems eg mobile radio broadcasting flight telephone WLL or WLAN sys tems Test signal ABFS can also simulate frequency hopping systems ABFS is fast enough to follow the frequency hopping of a test system for example within a frame of 4 616 ms GSM frame time Furthermore an offset voltage for each an
5. a ry Try 1LOSS B1 12 0 d H1Loss B2 0 0 dB aa eee Mi a TANNEL 12PATH 1INPUT SOUTPUT rire os lt ae ICHA 12PA MODE F GROUP A we Ns MODE dy DCHANNEL7 6PATH 1INPUT 2OUTPU frsrmsa p LOT a t SE LT PPR bal i l L L j mi TYP a ew ow ae OLIN mis P f i Baseband Fading Simulator ABFS Saving costs through real world fading tests e 2 fading channels e Universal use in research e Receiver tests at 1 Q level to 4 with option ABFS B2 development and production gether with a baseband source e 12 propagation paths e Simulation of present and e Ease of operation 24 with option ABFS B2 future communication systems e High reliability thanks to flexible concept ROHDE amp SCHWARZ Advantages of fading simulation in baseband 0 00 600x BOOOD Ol Ooo000o0 Conventional fading simulators nor mally convert the signal of the radio channel to the IF perform fading and faded Q faded then reconvert the signal to its RF fre quency It is however less costly to loop in the simulator prior to the first conversion to the carrier frequency ie to simulate at baseband level I and Q and then convert to the correct fre RF OUT OOO 9 O B OOB quency in the test system see Fig 2 Signals will therefore not be impaired by the effects
6. d Q input or output can be entered to compensate external DC offset voltages Together with a baseband source eg I Q Modulation Generator AMIQ from Rohde amp Schwarz see Fig 1 on the left receiver tests can be per formed at I Q level even if the corre sponding RF link is not available Dur ing the development of receivers or correction circuits in the receiver eg equalizer the effects of fading can thus be checked at a very early stage Input incl channel simulation LQ Test system 1 Q output k Qmodulator i Fading Simulator ABFS Fig 2 Fading simulation in baseband Fig 4 Schema of fading simulator path 1 path 2 l variable AH Oo variable delay path 6 A j variable gain gt delay ee Channel 1 6 path fading 6 path fading LQ Channel 2 Fig 3 Interconnections of ABFS DSP fading profiles O gain O from second od The basic model of ABFS comes with two independent channels for 6 path fading The two channels can be inter connected as follows see Fig 3 e Distribution of an input to two out puts eg with different fading pro files This feature makes it possible to simulate the signal of two anten nas with different characteristics or frequency diversity methods e Simulation of two channels with in dividual profiles and addition at output Cell change or superposi tion of interferers
7. ing simulation Number of propagation paths and fading channels Basic model with option ABFS B2 Insertion loss between input and output at O dB path attenuation Frequency response up to 5 MHz offset from carrier frequency corresponding to 10 MHz system bandwith Path attenuation Range Resolution Error in range O to 20 dB Path delay Range Resolution Error Doppler shift Frequency range Speed range Resolution Error Rayleigh fading Pseudo noise interval Deviation from theoretical CPDF at Pag O dB in range 20 dB to 10 dB in range 30 dB to 20 dB Rice fading Power ratio Range Resolution Frequency ratio Range Resolution Lognormal fading Suzuki fading Standard deviation Range Resolution 2 Local constant Correlation Range for magnitude Resolution Range for phase Resolution RF setting Range for each fading channel Frequency hopping mode Interface Addressing of frequency list Setting time after frequency change during Rayleigh fading 50 Q MP Q7 0 5V lt 2 mV fine tuning by software 0 3 dB 1 channel with 12 paths or 2 channels with 6 paths each 2 channels with 12 paths each or A channels with 6 paths each min 9 dB 0 1 dB to 0 6 dB O to 50 dB 0 1 dB lt 0 3 dB O to 1600 us 50 ns lt 5 ns 0 1 to 1600 Hz 0 03 10 m s 479 109m s Aan Vmax gt V fRF TRF min For example at fzr 1 GH v z 0 1 km h Vna 1724 km h 0 1 km h m s
8. nce Vibration sinusoidal Vibration random Shock Safety Dimensions W x H x D Weight Ordering information Baseband Fading Simulator Accessories supplied Options Noise Generator Second Fading Simulator Second Noise Generator Recommended extras 19 Rack Adapter Service Kit Trolley Transit Case Service Manual 17 to 50 dBfs 0 05 dB lt 0 3 dB JI Q 0 5 V 4 dBm O 6 12 to 42 dB white noise depending on set system bandwidth lt 0 5 dB bandwidth determining noise power 10 kHz to 10 MHz 1 50 0 2 dB to 0 6 dB IEC 625 IEEE 488 SCPI 1993 0 Amphenol 24 pin O to 30 O SH1 AH1 T6 L4 SR1 RL1 PP1 DC1 DT1 CO 90 V to 132 V AC 47 Hz to 440 Hz 180 V to 265 V AC 47 Hz to 440 Hz autoranging max 300 VA meets EN 50081 1 and EN 50082 2 O to 45 C meets IEC68 2 1 and IEC68 2 2 40 to 70 C 95 rel humidity cyclic test at 25 40 C meets IEC68 2 30 5 Hz to 150 Hz max 2 g at 55 Hz 55 Hz to 150 Hz 0 5 g const meets IEC68 2 6 IEC1010 1 and MIL T 28800D class 5 10 Hz to 300 Hz acceleration 1 2 g rms AO g shock spectrum meets MIL STD 810D MIL T 28800D class 3 and 5 meets EN 61010 1 435 mm x 192 mm x 460 mm 20 kg when unit is fully equipped ABFS power cable operating manual 1114 8506 02 ABFS B 1 1115 0009 02 ABFS B2 1115 0309 02 ABFS B3 1115 0609 02 ZZA 94 0396 4905 00 SM Z3 1085 2500 02 ZZK 1014 0510 00 ZZK
9. oppler frequency or speed be tween transmitter and receiver e Coupling to another channel Many fading models eg GSM Rural Urban Typical Urban have already been programmed in ABFS The user can quickly recall these default set tings and also modify the parameters Typical Rayleigh fading profile Rayleigh fading Doppler spectrum generated at a speed of 180 km h RF 1 8 GHz Center 1 8 GHz Why fading tests Short time signal fading as caused by multipath propagation strongly affects the error rate of the received signal due to the short symbol peri ods in digital mobile radio Modern digital systems overcome these problems with the aid of appropriate error control coding methods as well as algorithms for delay equalizing Morker 1 T1J RBW 1 MHz RF Ait 30 dB 18 08 dBm VBW 1 MHz Span 1 kHz Interleaving is employed to over come the problem of losing large parts of the messages Resistance to fading is an essential quality criterion of digital mobile radio systems and means a consid erable competitive advantage for the manufacturer Tests with real world signals using fading simulators are a must to spot the weak points in new concepts at an early stage so that appropriate modifications can be made Baseband Fading Simulator ABFS 4 Specifications IQ inputs and outputs Impedance Input voltage for full scale level Residual DC voltage at output Insertion loss of basic unit Fad
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