Q-Flex Satellite Modem Installation and Operating Handbook
12-4
12.3 Rx Demodulator Specifications
Parameter
Modem
IF Input Range
Minimum: -115+10 log (symbol rate)
Maximum: -80 + 10 log (symbol rate)
L-band Input Range
Minimum: -130 + 10 log (symbol rate)
Maximum: -80 + 10 log (symbol rate)
Maximum Composite
signal
+10dBm
Wanted-to-composite
Level
IF: -94 + 10 log (symbol rate)
L-band: -102 + 10 log (symbol rate)
Frequency Acquisition
Range
Selectable from ±1kHz to ±250kHz (10kHz steps)
Acquisition Threshold
<5dB Es/No QPSK
Acquisition Time
At 9.6kbps, less than 1s at 6dB Es/No. QPSK
At 10 Mbps, less than 100ms at 6dB Es/No. QPSK
Clock Tracking Range
±100ppm minimum
Receive Filtering
Spectral roll-off factors of 5%, 10%, 15%, 20%, 25%
and 35%. See the document ‘Saving Satellite
Bandwidth by Optimising Spectral Roll-off’ (document
number AN_035) from the White Papers section of
http://www.paradisedata.com
) for more details,
including occupied bandwith calculations.
Performance Monitoring
Measured Eb/No (range 0-15dB, ±0.2dB).
Measured Frequency Offset (100Hz resolution).
Wanted signal level strength indicator centred on the
middle of the Rx input range.
AGC Output
Buffered direct AGC output for antenna tracking, etc.
12.4 Clocking and Buffering Specifications
Parameter
Modem
Clock Integrity
Frequency Locked Loops give phase-hit immune
operation even with poor clock sources such as
routers etc.
Tx Clocking
Internal
±0.5ppb per day
External
Tracking range ±100ppm/min
Rx Clock
Slaves Tx timing from Rx clock.
(Includes full asymmetric operation)
Rx Clocking
Buffer
Disable
Clock from Satellite
Tx Input
clock
Plesiochronous.
(Includes full asymmetric operation)
Internal
±0.5ppb per day
External timing clock (DTE interface only)
Station Reference (see below)
Station Reference Inputs
75
Ω
BNC female Station Clock Connector, transformer
isolated.
1MHz to 10MHz in 1kHz steps (accepts sinusoidal
>0dBm or square-wave e.g., G.703 para 10