LA1135 데이터 시트보기 (PDF) - SANYO -> Panasonic
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LA1135 Datasheet PDF : 18 Pages
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LA1135, 1135M
7. Meaning of L2
If the RF stage is double-tunned, the difference in sensitivity within the RF band almost disappears, but an antireasonance
point of approximately 20 MHz appears, thereby leading to worse spurious characteristics. So, L2 is used to remove the SW
band.
8. Wide-band AGC
This IC contains 2-channel wide-band AGC. Pin 6 detects an undesired signal within the RF band and wide-band AGC is
applied. This detection sensitivity is determined inside the IC. Pin 2 detects an undesired signal outside the RF band. This
detection sensitivity is determined by R3. When 1 mVrms (f = 1 MHz) signal is applied to pin 2, AGC operates.
9. Measures against suppression of sensitivity
In the AGC circuit of the test circuit the presence of an undesired signal of high strength within the receiving band may cause
the desired signal to be suppressed when the desired signal is low or medium in strength. Shown below is the circuit
configuration where the necessary measures are taken against this suppression.
Wide-band
AGC input
Wide-band
AGC
circuit
S meter output
Circuit added
ANT
damping pin
ANT
damping
driver circuit
Sample constants
RA= 4.3 kΩ
RB = 3.0 kΩ
(VSM-130 = 5.0 V)
10. Transient response of S meter output at search, stop mode
The circuit configuration shown below is available to stabilize the transient response of the S meter output at the search, stop
mode.
Signal during searching from PLL
Unit (resistance: Ω)
11. When using LW (approximately 50°C or greater), additionally connect a resistor of 27 kΩ across pins 18 and 19 against
increase in local oscillation level. When using MW, no additional resistor is required.
12. Improvement in image frequency interference
Change the RF double-tuning coil as follows, and the image frequency interference becomes 63 dB at fr = 1400 kHz.
(Q of the tuning circuit must not be decreased with resistor 100 kΩ.)
Continued on next page.
No. 1272-7/18
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