Weak signal processing TDA7703
26/32 Rev 1
5.1.5 High cut control
Table 23. High cut control
(continuous set)
Symbol Parameter Test condition Min Typ Max Units
HCFSsp Start point vs. field strength
minimum RF level for widest
HC filter (filter # 7)
no multipath present
05050dBµV
HCFSep End point vs. field strength
maximum RF level for
narrowest HC filter (filter # 0)
no multipath present
03040dBµV
HCFStW2N
Field strength-related
transition time from wide to
narrow band
V
rf
step-like variation from
60 dBµV to 10 dBµV
(1)
-
HCFStN2W
Field strength-related
transition time from narrow to
wide band
V
rf
step-like variation from
0 dBµV to 60 dBµV
(1)
14 100 s
HCMPsp Start point vs. multipath
minimum RF level for widest
HC filter (filter # 7)
equivalent 19 kHz AM
modulation depth;
field strength = 80 dBµV
5 10 150
(2)
%
HCMPep End point vs. multipath
maximum RF level for
narrowest HC filter (filter # 0)
equivalent 19 kHz AM
modulation depth;
field strength = 80 dBµV
5 30 150
(2)
%
HCMPtN2W
Multipath -related transition
time from narrow to wide
band
V
rf
step-like variation from
20 dBµV to 80 dBµV
0.001 0.001 20 s
HCMPtW2N
Multipath -related transition
time from wide to narrow
V
rf
step-like variation from
80 dBµV to 20 dBµV
0.001 0.001 20 s
HCmaxBW
Maximum cut-off frequency of
high cut filter bank
Filter #7, -3 dB response
frequency, input signal with
pre-emphasis
HCmin
BW
14 18 kHz
HCminBW
Minimum cut-off frequency of
high cut filter bank
Filter #0, -3 dB response
frequency, input signal with
pre-emphasis
0.1 3
HCma
xBW
kHz
HCnumFilt Number of discrete HC filters - - 8
(3)
--
1. Depends only on field strength filter time constant.
2. Means that 100% equivalent 19 kHz AM modulation depth will not achieve full band narrowing.
3. Intermediate filters (#6 - #1) cut-off frequencies exponentially spaced between HCmaxBW and HCminBW.
