LA75695VA
No.7637-10/13
V29. VCO control sensitivity [
β]
(1) Apply the VCC voltage to the external AGC, IF AGC (pin 17).
(2) Pick up the VCO oscillation frequency from the VIDEO output (A), GND, etc. and adjust the VCO coil
so that the frequency becomes 45.75MHz.
(4) f1 is taken as the frequency when 3.0V is applied to the APC pin (pin 9).
In the same manner, f2 is taken as the frequency when 3.4V is applied to the APC pin (pin 9).
β =
(kHz/mV)
V30. Synchronization ratio [VS]
(1) Internal AGC
(2) fp = 45.75MHz 87.5% 10STEP B/W
Vi = 10mVrms
(3) Measure the output amplitude at the measuring point A. Vvideo
(4) Measure the pedestal voltage (DC) at the measuring point A. Vped
VS = (Vped–V6tip) / Vvideo×100 (%)
F1. 1st SIF conversion gain [VG]
(1) Internal AGC
(2) fp = 45.75MHz CW; 10mV (VIF input)
fs = 41.25MHz CW; 500
V (1st SIF input) V1
(3) Detection output level at test point C (Vrms) V2 (4.5MHz)
(4) VG = 20log
dB
F2. 4.5MHz output level [SO]
(1) Internal AGC
(2) fp = 45.75MHz CW; 10mV (VIF input)
fs = 41.25MHz CW; 10mV (1st SIF input) V1
(3) Detection output level at test point C (4.5MHz) SO (mVrms)
F3. 1st SIF maximum input [Si max]
(1) Internal AGC
(2) fp = 45.75MHz CW; 10mV (VIF input)
fs = 41.25MHz CW; variable (1st SIF input)
(3) Input level at which the detection output at test point C (4.5MHz) becomes SO ±2dB. Si max
F4.F5. 1st SIF input resistance, Input capacitance [Ri (SIF1), Ci (SIF1)]
(1) Using an input analyzer, measure Ri and Ci in the input impedance measuring circuit.
S1. SIF limiting sensitivity [Vi (lim)]
(1) Apply the VCC voltage to the external AGC, IF AGC (pin 17).
(2) fs = 4.5MHz fm = 400Hz
F = ±25kHz (SIF input)
(3) Set the SIF input level to 100mVrms and then measure the level at test point D. V1
(4) Lower the SIF input level until V1 -3dB occurs. Measure the input level at that moment.
S2.S4. FM detection output voltage, distortion factor [VO (FM), THD]
(1) Apply the VCC voltage to the external AGC, IF AGC (pin 17).
(2) fs = 4.5MHz fm = 400Hz
F = ±25kHz (SIF input Vi = 100mVrms)
(3) Assign the level at test point D to the FM detection output voltage and measure the distortion factor.
S3. AM rejection ratio [AMR]
(1) Apply the VCC voltage to the external AGC, IF AGC (pin 17).
(2) fs = 4.5MHz fm = 400Hz AM = 30% (SIF input Vi = 100mVrms)
(3) Measure the output level at test point D. VAM
(4) AMR = 20log
dB
f2–f1
400
V2
V1
VO (FM)
VAM