LA76075 Datasheet, PDF (15/35 Pages) Sanyo Semicon Device – NTSC Color Television Sets

LA76075
SIF (FM) Block Input Signals and Measurement Conditions
Unless otherwise specified for the items, apply the following conditions.
1.Use the following bus control condition: IF.AGC.DEF = “1.”
2. SW:IF1 = “ON”
3. Apply the input signal to pin 49. Use a carrier frequency of 4.5 MHz.
Item
FM output level
FM limiting sensitivity
FM f characteristic
(fm = 50 Hz)
FM f characteristic
(fm = 100 Hz)
FM total harmonic
distortion
AM rejection
SIF signal-to-noise ratio
Symbol
SOADJ
SLS
SF50
SF100K
STHD
SAMR
SSN
Measurement
Point
Input
Signal
Measurement Procedure
Bus Condition
7
90 dBµ,
fm = 400 Hz,
FM = ±25 kHz
Adjust the DAC FM.LEVEL to bring the 400 Hz
component of the pin 7 FM wave detection output as
close as possible to 474 mVrms. Measure SV1, the
output level (mVrms).
7
fm = 400 Hz,
FM = ±25 kHz
Determine the input level (dBµ) at which the 400 Hz
component of the pin 7 FM wave detection output is -3
dB relative to SV1.
FM.LEVEL = adjusted
value
7
90 dBµ,
fm = 50 Hz,
FM = ±25 kHz
Set SW:IF1 to “OFF.” Measure SV2, the output level
(mVrms) for the pin 7 FM wave detection output, and
substitute in the following formula.
SF50 = 20 × LOG(SV1/SV2) [dB]
FM.LEVEL = adjusted
value
7
90 dBµ,
fm = 100 Hz,
FM = ±25 kHz
Set SW:IF1 to “OFF.” Measure SV3, the output level
(mVrms) for the pin 7 FM wave detection output, and
substitute in the following formula.
SF100K = 20 × LOG(SV1/SV2) [dB]
FM.LEVEL = adjusted
value
7
90 dBµ,
fm = 400 Hz,
FM = ±25 kHz
Determine the total harmonic distortion for the 400-Hz
component of the pin 7 FM wave detection output.
FM.LEVEL = adjusted
value
7
90 dBµ,
fm = 400 Hz,
AM = 30%
Measure SV4, the 400 Hz component (mVrms) of the
pin 7 FM wave detection output, and substitute in the FM.LEVEL = adjusted
following formula.
value
SAMR = 20 × LOG(SV1/SV4) [dB]
7
90 dBµ,
CW
Measure SV5, the noise level (mVrms) at pin 7, and
substitute in the following formula.
SSN = 20 × LOG(SV1/SV5) [dB]
FM.LEVEL = adjusted
value
No. 5845-15/35