64
5) Operation of Main Blocks
!
Input Selector
It selects one of TV In, Line In 1/2/3 by Bus Data. And also, it selects output of Normal Audio IC.
@
Output Selector
It selects output mode each of Hi-Fi/L CH/R CH, Line 2/3 monitor by Bus Data.
#
EVR (Electronic Volume Resistor)
It controls audio record level by the voltage of port 40/42.
$
Hi-Fi ALC
It automatically controls level by EVR AGC mode selected by Bus Data, which also makes signal not be out of spec. Attack & recovery
time of ALC is set by the constant of port 44.
%
VCO (Voltage Control Oscillator)
VCO with good linear performance is used for these models. Center frequency of carrier does not require adjustment thanks to Zener
Zap. Tolerance is +/– 5Khz of center for both L CH and R CH regardless of NTSC and Pal.
^
Switching Noise Compensation
It compensates noise happened at rotating head. Compensation pulse is made by the constant inside of IC.
&
DOC (Drop Out Compensation)
If playback FM signal is under 4 microsecond, dropout is detected and compensated, i.e., playback audio signal is adjusted close to Vref
(Voltage Reference) from the dropout detect point. It names 'Smoothing Mute'.
The delay time for dropout is 18microsec and its detect level is –20dB.
*
Envelope Detection
It is used for adjusting tracking of head. It detects the Envelope Detection of playback FM signal after passing BPF. Channel of
Envelope Detection (L CH or R CH) is selected by Bus Data.
(
Hi-Fi Detection (Forced Normal)
If dropout of playback of FM signal is 70 microsecond, non Hi-Fi is detected and port 27 comes to be high. Under this condition, audio
output of Line Out is compulsorily changed to Normal Audio.
The delay time of detection is 1.6 microsecond which is set by constant together with detection time.
)
Monaural ALC
There is an ALC circuit on Monaural Output of port 19 apart from Hi-Fi.
Attack and recovery time are set by constant of port 21. If port 21 is grounded, ALC mode will not work.
1
AUX Audio Mute
TA1246F has two Mute functions. One is Bus Mute which stops signal by Bus Data, and the other is AUX Mute which is operated by
voltage applied from the outside. A Mute transistor, which does not need power of IC, is used for AUX Mute. Voltage addition to port
10 make Mute function possibly operated even without power of IC. (Mute TR cannot be controlled by Bus.)
2
Log Amp
It is used for Audio Level Meter. If Bus Mute or AUX Mute is on, nothing is usually output.
3
Just Clock Mode
It makes it output of Log Amp possibly used for Just Clock Mode (Adjustment to standard exact time). It is set by Bus Data.
If Just Clock Mode is set, L CH output of Log Amp will not work even though AUX Audio Mute is on (Bus Data is off).
Summary of Contents for DV-K784N-JJ
Page 35: ...34 AC001 K884NZ SJ M K884NZ SG M only...
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Page 66: ...65 ELECTRICAL ADJUSTMENTS Fig 1 Circuit Board Location...
Page 99: ...98 INTERCONNECT WIRING DIAGRAM K884N K784N K804N Hi Fi INTERCONNEC WIRING DIAGRAM REV 1 97 2 5...
Page 100: ...99 POWER SUPPLY SCHEMATIC DIAGRAM FREE VOLTAGE K884NY SJ M K884NZ SJ M K884NZ SG M...
Page 102: ...101 PRE AMP SCHEMATIC DIAGRAM K884N K784N 804N Hi Fi PREAMP SCHEMATIC DIAGRAM REV 1 97 2 5...
Page 103: ...102 VIDEO AUDIO SCHEMATIC DIAGRAM K884N K784N K804N...
Page 104: ...103 PIF MPX SCHEMATIC DIAGRAM K884N K784N K804N Hi Fi PIF MPX SCHENATIC DIAGRAM REV 1 97 2 5...
Page 105: ...104 TIMER SYSCON SCHEMATIC DIAGRAM K884N K784N K804N...
Page 106: ...105 Hi Fi AUDIO SCHEMATIC DIAGRAM K884N K784N K804N Hi Fi AUDIO SCHEMATIC DIAGRAM REV 1 97 2 5...
Page 107: ...106 POWER SUPPLY BLOCK DIAGRAM FREE VOLTAGE K884NY SJ M K884NZ SJ M K884NZ SG M...
Page 108: ...107 POWER SUPPLY BLOCK DIAGRAM 120V ONLY K884N SJ K884N JJ K884N SG K784N SJ K784N JJ K784N SG...
Page 109: ...108 PRE AMP BLOCK DIAGRAM K884N K784N K804N Hi Fi PREAMP BLOCK DIAGRAM REV 1 97 2 5...
Page 110: ...109 VIDEO AUDIO BLOCK DIAGRAM K884N K784N K804N Hi Fi VIDEO BLOCK DIAGRAM REV 1 97 2 5...
Page 111: ...110 PIF MPX BLOCK DIAGRAM K884N K784N K804N Hi Fi PIF MPX BLOCK DIAGRAM REV 1 97 2 5...
Page 113: ...112 Hi Fi AUDIO BLOCK DIAGRAM K884N K784N K804N AUDIO BLOCK DIAGRA REV 1 97 2 5...
