LA75600VA

No.A0325-8/17

V23.V24 APC pull-in range …… [fpu, fpl]

(1) Internal AGC

(2) fp = 39MHz to 51MHz continuous wave ; 10mVrms

(3) Adjust the SG signal frequency to be higher than fp = 45.75MHz to bring the PLL to unlocked state.

Note; The PLL is assumed to be in unlocked state when a beat signal appears at test point A.

(4) When the SG signal frequency is lowered, the PLL is brought to locked state again. …… f1

(5) Lower the SG signal frequency to bring the PLL to unlocked state.

(6) When the SG signal frequency is raised, the PLL is brought to locked state again. …… f2

(7) Calculate as follows:

fpu = f1

− 45.75MHz

fpl = f2

− 45.75MHz

V25. AFT tolerance frequency 1 …… [

∆fa1]

(1) Internal AGC

(2) SG1:43.75MHz to 47.75MHz variable continuous wave 10mVrmns

(3) Adjust the SG1 signal frequency so that the AFT output DC voltage (test point B) becomes 2.5V; that SG1 signal

frequency is f1.

(4) External AGC (Adjust the V17.)

(5) Apply 9V to the IFAGC (pin 17) and then pick up the VCO oscillation frequency from the GND, etc.; that

frequency is f2.

(6) Calculate as follows: AFT tolerance frequency

∆fa1 = f2 − f1 (kHz)

V26.V27 VCO Maximum variable range (U, L) …… [dfu, dfl]

(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.

(3) fl is taken as the frequency when 1V is applied to the APC pin (pin 9). In the same manner, fu is taken as the

frequency when 5V is applied to the APC pin (pin 9).

dfu = fu

− 45.75MHz

dfl = fl

− 45.75MHz

V28. 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.

(3) f1 is taken as the frequency when 2.8V is applied to the APC pin (pin 9). In the same manner, f2 is taken as the

frequency when 3.0V is applied to the APC pin (pin 9).

V29. RF AGC input level …… [ViRFAGC]

(1) Internal AGC.

(2) fp = 45.7MHz continuous wave (VIF input)

(3) Measure the input level at which the pin 14 voltage becomes 2.5V with the RF AGC resistance (pin 21 to GND)

being 5.1k

Ω.

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 Vi = 100mVrms)

(3) Set the SIF input level to 100mVrms and measure the level attest point D. ……V1

(4) Lower the SIF input level and measure the input level that becomes V1 − 3dB.

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)

(3) Measure the FM detection output voltage and the distortion rate at test point D.