V10.V11. Black noise threshold level and clamp voltage . . . . . . [VBTH, VBCL]

(1) Apply DC voltage to the external AGC, IF AGC (pin 17) and adjust the voltage.

(2) fp = 38.9MHz 400Hz 40% AM10mVrms (VIF input)

(3) Adjust the IF AGC (pin 17) voltage to operate the noise canceller.

Measure the VBTH, VBCL at test point A.

V12. Video S/N . . . . . . . . . . . . . . . . . . . . . . . . . . . . [S/N]

(1) Internal AGC

(2) fp = 38.9MHz CW = 10mVrms (VIF input)

(3) Measure the noise voltage at test point A in RMS volts through a 10kHz to 4MHz band-pass filter.

Noise voltage (N)

(4)

V13. C/S beat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [ICS]

(1) Apply DC voltage to the external AGC IF AGC (pin 17) and adjust the voltage.

(2) fp = 38.9MHz CW;10mVrms

fc = 34.47MHz CW;10mVrms-10dB

fs = 33.4MHz CW;10mVrms-10dB

(3) Adjust the IF AGC (pin 17) voltage so that the output level at test point A becomes 1.3Vp-p.

(4) Measure the difference between the levels at 4.43MHz and 1.07MHz.

V14. Frequency characteristics . . . . . . . . . . . . . . [fc]

(1) Apply DC voltage to the external AGC IF AGC (pin 17) and adjust the voltage.

(2) SG1: 38.9MHz continuous wave 10mVrms

SG2: 38.8MHz to 32.9MHz continuous wave 2mVrms

Add the SG1 and SG2 signals using a T pat and adjust each SG signal level so that the above-mentioned levels

are reached and input the added signals to the VIF IN.

(3) First set the SG2 frequency to 38.8MHz, and then adjust the IF AGC voltage (V17) so that the output level at test

point A becomes 0.5Vp-p.........V1

(4) Set the SG2 frequency to 32.9MHz and measure the output level..........V2

(5) Calculate as follows:

No.7779-7/21

LA7567EV

VBCL

VBTH

Time

Video output

(V)

S/N = 20 log

= 20 log

(dB)

Noise voltage (Vrms)

Video portion (Vp-p)

Noise voltage (Vrms)

1.12Vp-p

1.07MHz

4.43M

5.5M

Frequency(MHz)

Output

(dB)

C/S beat

(dB)

V1

V2

20log

fc =