SingMai Electronics
PT9 User Manual Revision 0.3
Page 13 of 38
Figure 5 Luma interpolation filter frequency response.
A switchable sinx/x filter allows compensation for the DAC sampling error. Its response is shown in
Figure 6.
Figure 6 Sinx/x filter frequency response.
The last block of the output-proc module is the pre-emphasis block. When driving long lengths of
cable with the PT9 there will be a high frequency loss. This is usually compensated for with a high
frequency boost network at the receiver (decoder). To provide better compensation the PT9 has a
pre-emphasis filter that is matched to response of typical coaxial cable (e.g. RG-59). The filter
provides a high frequency boost whose amplitude is controllable via a register. The response of
this filter is shown in Figures 7 and 8.
It is possible, when used with the SingMai video decoders, that this frequency compensation can
be automatic. Contact SingMai for more details.
Inphase Filter Frequency Response
Frequency in MHz
M
a
g
n
it
u
d
e
i
n
d
B
0
2
4
6
8
10
-60
-50
-40
-30
-20
-10
0
10
Inphase Filter Frequency Response
Frequency in MHz
M
a
g
n
it
u
d
e
i
n
d
B
0
2
4
6
0.0
0.4
0.8
1.2
1.6
2.0
2.4
2.8
3.2
