CCE HPS-2971 - Closed Caption Reception Sensitivity; AGC Circuit Voltage; AFT Circuit Burst Signal Variation

HPS-2971
a) Adjust the TV to a “PP” condition.
b) Apply a 60dBµV signal (frequency and channel defined by factory) 88%
modulated with color bars (Pal-M) with Closed Caption signal.
c) Observe on the TV screen in test and reduce the generator output level until
the minimum value that be possible identify the characters of the C.C
without errors, being generator output level the value of the sensitivity of
Closed Caption reciever.
Condition Nominal Limit Unit
PAL-M 48 51
dBµV
3.6.4 AGC circuit
a) Apply to the antenna input a 60dBµV signal with 88% AM modulation with
“WHITE” pattern (frequency and channel factory defined), and FM sine
wave 400 Hz audio modulation +-25 kHz deviation.
b) Adjust the TV to “PP” condition.
c) Read the DC voltage at the tuner AGC terminal. Utilize a DC electronic
voltmeter with minimum 10 MΩ impedance.
Minimum Nominal Maximum Unit
1,50 2,50 3,50 V
DC
3.6.5 AFT circuit
a) Apply to the antenna input a 60dBµV signal with 88% AM modulation with
PAL-M COLOR BAR pattern (frequency and channel factory defined), and
FM sine wave 400 Hz audio modulation +-25 kHz deviation
b) Connect a oscilloscope in the output video detector and read the peak to
peak burst level signal “Vb”
c) Increment the generator frequency by 500 kHz and read the new value
peak to peak burst signal “Vh” and calculate the percentage as following:
E
H
= V
H
/V
B
d) Decrement the generator frequency by 500 kHz and repeat the
procedure(c) reading the peak-to-peak burst signal V
L
and calculate the
percentage as following:
E
L
= V
L
/V
B
Minimum Nominal Maximum Unit
E
H
-0,80 0,00 +1,00 %
E
L
-0,80 0,00 +1,50 %