WT8043
Horizontal Frequency Discriminator
There are 3 horizontal frequency discriminator pins on 20 pin type package:
36.2kHz, 45kHz, 52kHz (for N20P1), 33kHz, 36.2kHz, 45kHz (for N20P4); 2
frequency discriminator pins on 16 pin type package: 33kHz, 36.2kHz and 6
frequency discriminator pins on 24 pin type package: 33kHz, 36.2kHz, 45kHz,
52kHz, 62kHz and 72kHz. Please refer to table 3 for the logical truth table of
these pins. These frequency discriminator pins can pull up to +12V through a
resistor, sink current to the open drain structure must keep under 6mA (ref. P4
Electrical Characteristics). These frequency discriminator pins output can be used
for CS Capacitor Control directly as well as other application.
Table 3: Truth table of Frequency discriminator
Signal
F33K F36.2K F45K F52K F62K F72K
Hsync
Hs < 33k
1
0
0
0
0
0
0
1
1
0
0
0
0
0
1
1
1
0
0
0
0
1
1
1
1
0
0
0
1
1
1
1
1
0
0
1
1
1
1
1
1
0
36.2k > Hs > 33k
45k > Hs > 36.2k
52k > Hs > 45k
62k > Hs > 52k
72k > Hs > 62k
Hs > 72k
SYNC Output State Description
Both H_out / V_out duplicate Hsin/Vsin in the same frequency and pulse width,
but are fixed at negative polarity. And H_out/ V_out have their own cut-off
frequency: 15kHz for H_Sync and 30Hz for V_Sync. While the frequency of input
signal is less than the cut-off frequency, the output will keep in low state. Please
refer to the Table 4.
Table 4:
Hsin
Vsin
H_out
V_out
>15kHz
>15kHz
<15kHz
<15kHz
>30Hz Negative polarity Hsin Negative polarity Vsin
<30Hz Negative polarity Hsin Low state
>30Hz Low state
<30Hz Low state
Negative polarity Vsin
Low state
Weltrend Semiconductor, Inc.
2F., No. 24, Industry E. 9th Rd.
Science-Based Industrial Park
Hsin-Chu, Taiwan, R.O.C.
Tel: 886-35-780241
Fax: 886-35-770419
16
ETC [ ETC ]
