Technicolor - Thomson ICC19, Principles And Maintenance

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INTERMEDIATE FREQUENCY
Created using three surface wave filters and an integrated circuit:
• FI010, two-sided Nyquist filter for picture selectivity in L' Band 3, L, D, K,
and I (38.9 MHz) and L' Band 1 (33.9 MHz).
• FI015, for picture selectivity in B and G.
• FI020, switchable filter, for sound selectivity in L' Band 3, L, D, K, I, B, and
G (32.4 MHz), and L' Band 1 (40.4 MHz).
• II050, TDA9811.
After leaving the tuner, the IF signal passes through two traps (40.4 MHz, out
of operation in Band 1 L', and 31.9 MHz, in operation in B/G), is amplified by
TI020, and informs Circuit II050 via the selectivities. The picture IF is injected
at 1/2 and at 3/4 of II050. The sound IF is injected at 31/32 of II050.
Transistors TI040 and TI045 and Diodes DI040 and DI041 select the audio
selectivity (DI040 passes in Band 1 L').
Integrated Circuit II050 performs the following functions:
• Picture IF amplification and demodulation (FI030 is used),
• FM sound and NICAM amplification,
• IF and HF AGC.
The demodulated video signal is available on Output 21 of II050. It passes
through the FM audio intercarrier trap (FI040, 5.5 and 6.5 MHz) and is
reinjected at 22 on II050. After amplification, this video signal is output at 10
of II050. It passes through the FM audio intercarrier trap (QI053, 6 MHz), and
is sent to the switching stage via PI035, TI032, TI030, or PI030, TI031, TI030.
PI035 adjusts the video level for L, L'.
PI030 adjusts the video level for B, G, D, K, and I.
TI033 and RI032 attenuate the video level for I.
The demodulated audio signal (from AM) is available on Output 12 of II050.
The NICAM and FM audio intercarriers are available on Output 20 of II050.
They are amplified by TI070 via Switching Diodes DI070 (NICAM 5.85 MHz)
and DI071 (FM), and are sent to the demodulation stage (MSP3410).
The HF AGC voltage is available on Output 19 of II050. PI050 adjusts it.
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