
MITSUBISHI ICs (TV)
M52761SP/FP
PLL-SPLIT VIF/SIF IC
4
CL-U Capture range
1. Increase the frequency of SG9 until the VCO is out of locked-
oscillation.
2. Decrease the frequency of SG9 and measure the frequency fU
when the VCO locks.
CL-U=fU-58.75 (MHz)
CL-L Capture range
1. Decrease the frequency of SG9 until the VCO is out of locked-
oscillation.
2. Increase the frequency of SG9 and measure the frequency fL
when the VCO locks.
CL-L=58.75-fL (MHz)
CL-T Capture range
CL-T=CL-U+CL-L (MHz)
VCO
1. Input SG2 into VIF IN .
2. Turn on SW14 (Vcc), and adjust VCO coil so that AFT OUT
voltage TP2 equal 1/2 Vcc in 10 seconds.
3. Put VIF IN input in a non-input state and ground AGC filter at
TP8.
4. Measure the VCO free-run frequency 10 seconds after SW ON
(f1), and one minutes after (f2).
VCO
f (kHz) =f2 (MHz) -f1 (MHz)
f VCO SW on drift
μ
voltage
1. Input SG10 into VIF IN , and set the frequency of SG10 so that
the voltage of AFT output TP19 is 6V. This frequency is named f
(6).
2. Set the frequency of SG10 so that the AFT output voltage is 3V.
This frequency is named f (3)
3. IN the graph, maximum and minimum DC voltage are V
V
2L
, respectively.
AFT sensitivity, V
2H
Maximum AFT voltage, V
2L
Minimum AFT
2H
and
IM Intermodulation
1. Input SG11 into VIF IN, and measure EQ output TP18A with an
oscilloscope.
2. Adjust AGC filter voltage V8 so that the minimum DC level of the
output waveform is 1.0V.
3. At this time, measure TP18A with a spectrum analyzer .
The intermodulation is defined as a difference between 0.92MHz
and 3.58MHz frequency components.
LIM Limiting sensitivity
1. Input SG17 (Vi=90dB
component level of AF output TP10.
2. Input SG19 (Vi=90dB
component level of AF output TP10.
3. Measure the input level of SG17 and SG19 when a ratio of the
two VoAF level is 30dB. This input level is named V
μ
) into SIF input, and measure the 400Hz
μ
) into SIF input, and measure the 400Hz
IN MIN
.
AMR AM rejection
1. Input SG18 into SIF input, and measure the output level of AF
output TP10. This level is named VAM.
2. AMR is;
AF S/N
1. Input SG19 into SIF input, and measure the output noise level of
AF output TP10. This level is named VN.
2. S/N is;
C
Decrease the voltage of V7, and measure V7 when the DC voltage
of TP13 changes.
QIF
QIF control
f (6)
f (3)
f (MHz)
V
2L
V
2H
TP2
Voltage
6V
3V
μ =
1000 (mV)
f (3) - f (6) (kHz)(mV/kHz)
30dB
(dB
μ
)
(mVrms)
Audio Output when
SG17 is input
Audio Output when
SG19 is input
AMR=20log
VoAF (mVr.m.s)
VAM (mVr.m.s)
(dB)
S/N=20log
VoAF (mVr.m.s)
VN (mVr.m.s)
(dB)