la7688b Sanyo Semiconductor Corporation, la7688b Datasheet - Page 10

• Manufacturer Part Number: la7688b
• Description: Pal/ntsc Color Television-use Single-chip Lsi
• Manufacturer: Sanyo Semiconductor Corporation

Continued from preceding page.
VCO1 control sensitivity
[SIF block]
SIF limiting sensitivity
FM detection sensitivity
AM rejection ratio
FM detection output
distortion
SIF S/N
FM detection range
FM detection output
variation
Parameter
β1
Vilim
V 52
AMR
THD
S/N
(SIF)
WFM
∆V O
Symbol
TPO-8
TPO-52
TPO-52
TPO-52
TPO-52
TPO-52
TPO-52
TPO-52
point
Test
No-signal
SG1
fo = 5.5MHz
fm = 400Hz
FM : ∆f = ±30kHz
Same as above
100dBµ
SG1
fo = 5.5MHz
fm = 400Hz
AM = 30% MOD
100dBµ
SG1
fo = 5.5MHz
fm = 400Hz
FM : ∆f = ±30kHz
100dBµ
SG1
fo = 5.5MHz, cw
SG1
fo = 5.5MHz,
∆f = ±3kHz
fm = 400Hz
SG1
fo = 5.5MHz,
∆f = ±30kHz
fm = 400Hz
symbol
Input
LA7688B
Connect a spectrum analyzer to TP0-8
and check to see that the VCO
oscillation frequency is 38.9MHz.
And then apply DC voltage to TPZ-3A
and vary it from 3.2V to 2.8V.
Assign the frequency range at that
moment to ∆f.
β =
With the SG1 output level being
100dBµ, measure the level at TP0-52
using an AC voltmeter.
And then lower the SG1 output level
and measure the SIF input level when
the reading on the AC voltmeter drops
3dB.
(AC voltmeter input resistance = 1MΩ)
Measure the level at TP0-52 using an
AC voltmeter. (AC voltmeter input
resistance = 1MΩ)
Measure the level at TP0-52 using an
AC voltmeter and assign the measured
value to V52’.
(Input resistance=1MHz) AMR is
calculated relative to the VO1 value of
Test No.2 as shown below.
Measure the distortion at TP0-52 using
a distortion meter.
Measure the level at TP0-52 using an
AC voltmeter. Assign the measured
value to Vn.
(Use a filter of 20Hz to 20kHz.)
S/N = 20logV52/Vn (dB)
Connect an oscilloscope to TP0-52 and
lower the SG1 frequency to measure
the lower pull-in characteristic.
Assign the measured value to fL.
In the same manner, raise the SG1
frequency to measure the upper pull-in
characteristic.
Assign the measured value to fU.
WFM : fL≤4.0MHz
fU≥7.0MHz
Connect an AC voltmeter to TP0-52
and vary the SG1 frequency from
4.5MHz to 6.5MHz. Take Vo as the
reading on the AC voltmeter.
∆V O : -1.5dB≤Vo≤1.5dB
AMR
400
∆
fkHz
=
mV
V
V
2 5
Test method
52
′
(
(
mVrms
mVrms
)
)
[
dB
]
Continued on next page.
VR center
VR center
VR center
VR center
VR center
VR center
VR center
VR center
TPO-2
Applied voltage (V)
No.0077-10/20
TPZ-46
7.8V
7.8V
7.8V
7.8V
7.8V
7.8V
7.8V