Atec Rohde-Schwarz-SFQ Series - Manual (Page 12)

12 TV Test Transmitter R&S ® SFQ
DVB-C spectrum without and with noise
(24 dB C/N), associated I/Q constellations
Noise generator
The noise generator produces broadband
white noise with a Gaussian distribution.
The power density of the noise signal can
be set indirectly as C/N (carrier-to-noise)
ratio.
This is extremely convenient for the user as
the C/N ratio can be entered in dB immedi-
ately after selection of the demodulator
receive bandwidth. The receive bandwidth
is set to match the symbol rate but can be
modified. The R&S SFQ can thus simulate
different types of interference as they really
occur along the satellite, cable or antenna
transmission path to the receiver. The C/N
ratio is set according to the two fading
power models (FADING POWER). Featur-
ing internal C/N calibration for
each type of modulation, the
R&S SFQ makes for extremely
high accuracy.
Paths 7 to 12
Q
I
TV Test Transmitter R&S SFQ 2
10 MHz reference
RF
Additional
inputs:
TS PARALLEL
AUX,
BER DATA/
CLOCK/
ENABLE
Fading
simulator
Paths 1 to 6
I/Q modulator RF converter
Noise Generator
Option R&S SFQ-B5
Attenuator
+
I/Q coder
DVB-T, ISDB-T
and/or
ATSC/8VSB, J.83-B
and/or
DVB-C, DVB-S/-DSNG
Input
Interface
Option R&S SFQ-B6
Paths 7 to 12
Q
I
Ext. I/Q
TV Test Transmitter R&S SFQ 1
10 MHz reference
RF
Additional
inputs:
TS PARALLEL
AUX,
BER DATA/
CLOCK/
ENABLE
Fading
simulator
Paths 1 to 6
I/Q modulator RF converter
Noise Generator
Option R&S SFQ-B5
Attenuator
+
I/Q coder
DVB-T, ISDB-T
and/or
ATSC/8VSB, J.83-B
and/or
DVB-C, DVB-S/-DSNG
Input
interface
Option R&S SFQ-B6
Splitter
R&S SFQ-
B5+Z5
Ext. I/Q
I Q
0.3 MHz to
3300 MHz
0.3 MHz to
3300 MHz
ASI, SMPTE310
Ext. clock
SPI, TS PARALLEL
BER DATA/CLOCK/
ENABLE
ASI, SMPTE310
Ext. clock
SPI, TS PARALLEL
BER DATA/CLOCK/
ENABLE
Circuit diagram with two R&S SFQs and R&S SFQ-Z5 cable set for generating diversity signals
– RF frequency above 10 MHz doubled
– Same fading profile, but uncorrelated
– Uncorrelated noise generators for every receive path
– Cascadable for several diversity signals