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Note 1: Modulation Index impact on BER measurement using MS-FM demodulator.
The graphic hereafter shows the impact of the modulation index using the MS-FM demodulator:
The ��
/��
ratio has been set so that the BER = 10
��
0
Looking at the blue
forced to 0.7)
The modulation index of the transmitted PCM/FM signal has been changed around the 0.7 nominal
value. For each transmitter index value, the ��
−5
is 10
.
-
In the [0.67, 0.73] interval, MS-FM demodulator remains efficient.
-
Outside this range, there is a significant BER degradation.
Looking at the red
signal estimated by the demodulator)
As for the blue curve, the transmitted modulation index has been changed and the ��
increased till the BER is 10
-
MS-FM remains efficient over the entire range [0.6, 0.8]
14
12
10
8
6
4
2
0
0,6
© Safran Data Systems
COMMAND RANGING & TELEMETRY UNIT CORTEX
CRT QUANTUM USER'S MANUAL
curve,
the MS-FM demodulator operates in nominal mode
curve,
the MS-FM demodulator is in auto mode
−5
.
0,65
Modulation index of PCM/FM signal
Figure 23 : Required Eb/No to obtain BER = 10
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It cannot be duplicated or distributed without expressed written consent.
−5
with 0.7 Mod index.
/��
ratio has been increased till the measured BER
��
0
0,7
0,75
-5
with MS-FM demodulator
Safran Data Systems
.
Ref.
DTU 100042
Is.Rev.
5.17
Date:
Dec.
03, 2021Sept. 30, 2021
(modulation index
(modulation index of received
/��
ratio has been
��
0
Nominal mode
Auto mode
0,8
Page 35
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