Akai LTA-26C902, Руководство по обслуживанию

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The mono intercarrier sound circuit has a selective FM-PLL demodulator which can be switched to the
different FM sound frequencies (4.5/5.5/6.0/6.5 MHz). The quality of this system is such that the external
band-pass filters can be omitted. In the stereo versions of UOCIII the use of this demodulator is optional
for special applications.
Normally the FM demodulators of the stereo demodulator/decoder part are used (see below).
● The FM-PLL demodulator can be set to centre frequencies of 4.72/5.74 MHz so that a second sound
channel can be demodulated. In such an application it is necessary that an external bandpass filter is
inserted.
● The vision IF and mono intercarrier sound circuit can be used for the demodulation of
FM radio signals. With an external FM tuner also signals with an IF frequency of 10.7
MHz can be demodulated. For the QIP90 versions this is valid only for the “stereo”
versions
● Built-in adaptable brightness delay circuit
● switchable brightness signal transmission rate
Pin Description
：
Pin Name Description
1,2,12,18,28,40
68,81,89,92,95,101
121,125 VSS,GND ground
3,4,45,69,82,88,90,
91,93,94,96,100,
110,117,118,124 VDD Power supply
5 VREF_POS_LSL
6 VREF_HPL
7 VREF_HPR
8 VREF_HPR
9 VREF_POS_HPR SDAC input signal
10 XTALIN Crystal oscillator input
11 XTALOUT Crystal oscillator output
13 VGUARD/SWIO V-guard input / I/O switch
14 DECDIG decoupling digital supply
15 VP1 decoupling digital supply
16 PH2LF
17 PH1LF
phase-2 filter
phase-1 filter
19 SECPLL
20 DECBG SECAM PLL decoupling
bandgap decoupling
21 EWD/AVL East-West drive output or AVL capacitor
22 VDRB
23 VDRA
vertical drive B output
vertical drive A output
24 VIFIN1
25 VIFIN2 IF input 1
IF input 2
27 IREF reference current input
29 SIFIN1/DVBIN1
30 SIFIN2/DVBIN2 SIF input 1 / DVB input 1 SIF
31 AGCOUT tuner AGC output