LA1781M(2001) 查看數據表（PDF） - SANYO -> Panasonic
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LA1781M Datasheet PDF : 50 Pages
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LA1781M
Operating Characteristics and Symbols Used in the Test Circuit Diagrams
Switches (SW)
Switch on = 1, SW off = 0
There are two switches that use signal transfer.
— SW2: switches between the mixer input and the IF input.
— SW4: switches between noise canceler input and IF output + noise canceler input.
Types of SG used
PG1 (AC1)
AC2
AC3
AC4
AC5
Used for noise canceler testing. A pulse generator and an AF oscillator are required.
Used for FM front end testing. Outputs an 83 MHz signal.
Used for FM IF, noise canceler, and MPX testing. Outputs a 10.7 MHz signal. Stereo modulation must be possible.
Used for AM testing. Outputs 1 MHz and 1.4 MHz signals.
Used with the MRC. Can also be used for AF and OSC.
Power supply
VCC
VCC1
VCC2
VCC3
8V
5V
0.1 V / 0.7 V / 2 V / 4 V
0.1 V / 0.6 V / 2 V
• Switches
These levels
must be variable.
SD, stereo, seek/stop
Keyed AGC, Mute ATT
HCC, SNC, SASC (MRC)
SW1
SW2
SW3
SW4
SW5
SW6
SW7
SW8
SW9
SW10
Parameter
ON
OFF
AM/FM switching. The FE VCC is supplied to pin 62.
FM IF switching. Pin 51/FE output
FM
FE IF OUT (A)
AM
AC3 (B)
For conversion gain testing
Conversion gain measurement (A)
Other/purposes
For switching between noise canceler input and IF output + noise canceler.
AC1 (A)
Other/purposes
High-speed SD
High-speed SD
Other/purposes
SEEK/STOP (IF BUFF ON/OFF)
STOP
Seek (IF buffer output)
MUTE ATT 200 kΩ
MUTE 200 kΩ
OFF
MUTE ATT 30 kΩ
MUTE 30 kΩ
OFF
For pilot cancellation testing
When pilot cancellation is used When pilot cancellation is not used
Mute off (pin 33)
MUTE OFF
MUTE ON
• Trimmers (variable resistors)
VR1
Separation adjustment
VR2
Pilot cancellation adjustment
Test Points
• DC voltages
VD1
FM RF AGC voltage
Pin 2
VD2
AM/FM SD, AM Tweet, FM stereo indicator Pin 26
VD3
AM/FM S-meter
Pin 24
VD4
MRC output
Pin 27
VD5
Mute drive output
Pin 33
VD6
AM antenna damping voltage
Pin 46
VD7
N.C. Gate time
Pin 8
• AC voltages
VA1
AM/FM OSC Buff Pin 4
VA2
First IF output
Pin 53 → CF → pin 51 load level (10.7 MHz)
VA3
IF counter buffer
Pin 23 (10.7 MHz/450 kHz)
VA4
MPX OUT Left ch Pin 15 (AF)
VA5
MPX OUT Right ch Pin 16 (AF)
No. 6038-5/50
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