18
Phase method
３
-
５
. Tranceiver TX digital signal processing Phase
The right picture is the principle block
diagram,
The lower right is the block diagram actually
made.
While changing the sampling frequency or
filtering in the middle, basic signal
processing remains as it is in the principle
block diagram.
Please be aware that the frequency scale of
the spectrum display changes when the
sampling frequency changes.
When SW6, SW7 is pressed,
the point of view changes
and the spectrum changes.
D/A
+12kHz
Hilbert
delay
0
0
0
12k
A/D
Freq conv.
+12kHz
A/D
FIR 31 tap
fc=3kHz
Hilbert
127 tap
downsampling
fs:48k
→
12k
D/A
upsampling
fs:12k
→
48k
fs=48kHz
fs=48kHz
fs=12kHz
IIR 6 order
LPF
64tapDelay
FIR 31 tap
fc=3kHz
The difference
between 6 and 7,
6 is I/Q,
7 is I only.
1.ADC
2.fs=12k
3.FILTER
4.MOD
5.fs=48k
6.+12k
7.DAC
