digital receivers
Post on 15-Jun-2015
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Digital receivers
Sagax Communications, Ltd.
Haller u. 11-13. Budapest 1096 Hungary
www.sagax.hu
40 80 120 160 200 240 280 320 360 400
Instantaneous bandwidth =<Fs/2 Input bandwidth = 300MHz
Fs = 80MHz
1st
Nyquistzone
2nd Nyquist
zone
3rd Nyquist
zone
4th Nyquist
zone
5th Nyquist
zone
6th Nyquist
zone
7th Nyquist
zone
8th Nyquist
zone
9th Nyquist
zone
10th Nyquist
zone
Frequency response of the ADC input stage
F [MHz]
A
SIN
NCO
COS
MUL
MUL
Splitter
FLT
FLT
DEC
DEC
Input samples
I samples
Q samples
A A
DD
FIFOFIFO
DDCDDCFPGAFPGA
RF Front-end SDR-based Digital Receiver
DSPDSP GUIGUI
VHF/UHFVHF/UHF
LF/HFLF/HF
LAN
20-3000MHz
6KHz-32MHz
Audio
LINE
Audio,Data,
Remote
Control GPS,Compass
SERIAL
Converter card
Receiver platform computer
LPF 32MHzHPF 1.6MHz
40 80 120 160 200 240 280 320 360 400
1st
Nyquistzone
2nd Nyquist
zone
3rd Nyquist
zone
4th Nyquist
zone
5th Nyquist
zone
6th Nyquist
zone
7th Nyquist
zone
8th Nyquist
zone
9th Nyquist
zone
10th Nyquist
zone
A
RF ATT0/10/20/30dBRF Pre-selector (optional) RF LNALIMITER
Input selector
Filtered input
Direct input
A
B
RF ATT0/10/20/30dBLPF 110MHzRF Pre-selector (optional) RF LNAHPF 88MHzLIMITER
40 80 120 160 200 240 280 320 360 400
1st
Nyquistzone
2nd Nyquist
zone
3rd Nyquist
zone
4th Nyquist
zone
5th Nyquist
zone
6th Nyquist
zone
7th Nyquist
zone
8th Nyquist
zone
9th Nyquist
zone
10th Nyquist
zone
AInput selector
Filtered input
Direct input
A
B
RF ATT0/10/20/30dB
IF ATT0/10/20/30dB
LPF 3000MHzRF Pre-selector (optional) RF LNALO1
3400-6400MHz
LO22540MHz
BPF3400MHz
10MHzExt. Ref.
BPF 860MHz
LO3930MHz
BPF 60MHz(21.4MHz, 140MHz
optional)
10MHzExt. Ref.
10MHzExt. Ref.
IF AMP
IF AMP
C
D
1 2
3
AB
1
2
3
4
AB
A
B
C
D
CD
C
D
E
F
G
C
D
H
I
J
C
D
Frequency display on SRM
Frequency display on SRS
Frequency display on SRS in wb search mode
Spectrum display on SRS without (1) display decimation
Spectrum display on SRS with 2 display decimation
Spectrum display on SRS with 4 display decimation
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