
LA76818A
No.8047-11/44
Continued from preceding page.
Input signal
Symbol
Test point
Input signal
Test method
Bus conditions
APC pull-in
range (U), (L)
fPU, fPL
46
SG4
80dB
Connect an oscilloscope to pin 46 and adjust the
SG4 frequency to a frequency higher than
38.9MHz to bring the PLL into unlocked mode.
(A beat signal appears.) Lower the SG4 frequency
and measure the frequency at which the PLL locks
again. In the same manner, adjust the SG4
frequency to a lower frequency to bring the PLL
into unlocked mode. Higher the SG4 frequency
and measure the frequency at which the PLL locks
again.
NT Trap1 (4.5MHz),
2 (4.8MHz)
NTR1
NTR2
46
SG7
Determine the output level difference between
carrier frequencies of 1Mhz, 4.5MHz and 4.8MHz.
(Reference: 1MHz)
SIF.SYS = ”00”
BG Trap1 (5.5MHz),
2 (5.85MHz)
BTR1
BTR2
46
SG7
Determine the output level difference between
carrier frequencies of 1Mhz, 5.5MHz and
5.85MHz. (Reference: 1MHz)
SIF.SYS = ”01”
I Trap1 (6.0MHz),
2 (6.55MHz)
ITR1
ITR2
46
SG7
Determine the output level difference between
carrier frequencies of 1MHz, 6.0MHz and
6.55MHz. (Reference: 1MHz)
SIF.SYS = ”10”
DK Trap1 (6.5MHz)
DTR1
46
SG7
Determine the output level difference between
carrier frequencies of 1MHz and 6.5MHz.
(Reference: 1MHz)
SIF.SYS = ”11”
SIF Block (FM block) Input Signals and Test Conditions
Unless otherwise specified, the following conditions apply when each measurement is made.
1. Bus control condition:
IF.AGC.SW = "1", SIF.SYS = "01", DEEM-TC = "0", FM.GAIN = "0", A.MONI.SW = "0", A2.SW = "0"
2. IFSW1 = "ON", pin 29 = 5V
3. Input signals are input to pin 54 and the carrier frequency is 5.5MHz.
Parameter
Symbol
Test point
Input signal
Test method
Bus conditions
FM detection
output voltage
SOADJ
2
90dB
,
fm = 400Hz,
FM =
±30kHz
Measure the 400Hz component of the FM
detection output at pin 2.
SV1 [mVrms]
FM limiting
sensitivity
SLS
2
fm = 400Hz,
FM =
±30kHz
Measure the input level (dB
) at which the 400Hz
component of the FM detection output at pin 2
becomes -3dB relative to SV1.
FM detection
output f characteristics
(fm = 100kHz)
SF
2
90dB
,
fm = 100kHz
FM =
±30kHz
Set SW: IF1 = "OFF".
Measure the FM detection output of pin 2.
SV2 [mVrms]
SF = 20*Log (SV1/SV2) [dB]
FM detection output
distortion
STHD
2
90dB
,
fm = 400Hz,
FM =
±30kHz
Measure the distortion factor of the 400Hz
component of the FM detection output at pin 2.
AM rejection
ratio
SAMR
2
90dB
,
fm = 400Hz,
AM = 30%
Measure the 400Hz component of the FM
detection output at pin 2.
SV3 [mVrms]
Assign the measured value to SV3.
SAMR = 20*Log (SV1/SV3) [dB]
SIF.S/N
SSN
2
90dB
,
CW
Measure the noise level (DIN AUDIO,) at pin 2.
SV4 [mVrms]
SSN=20*Log (SV1/SV4) [dB]
PAL de-emph time
constant
SPTC
2
90dB
,
fm = 3.18kHz
FM =
±30kHz
Measure the 3.18kHz component of the FM
detection output at pin 2.
SV5 [mVrms]
SNTC = 20*Log (SV1/SV5) [dB]
PAL/NT
Difference of voltage
gain
SGD
2
fo = 4.5MHz
90dB
,
fm = 400Hz
FM =
±15kHz
Measure the 400Hz component of the FM
detection output at pin 2.
SV6 [mVrms]
SNTC = 20*Log (SV1/SV6) [dB]
SIF.SYS = "00"
DEEM-TC = "1"
FM.GAIN = "1"
NT de-emph
time constant
SNTC
2
fo = 4.5MHz
90dB
,
fm = 2.12kHz
FM =
±15kHz
Measure the 2.12kHz component of the FM
detection output at pin 2.
SV7 [mVrms]
SNTC = 20*Log (SV6/SV7) [dB]
SIF.SYS = "00"
DEEM-TC = "1"
FM.GAIN = "1"