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參數(shù)資料
| 型號： | LA1143 |
| 廠商： | Sanyo Electric Co.,Ltd. |
| 英文描述： | FM IF System for Car Radios |
| 中文描述： | 如果系統(tǒng)的汽車收音機調(diào)頻 |
| 文件頁數(shù)： | 4/5頁 |
| 文件大小： | 124K |
| 代理商： | LA1143 |
LA1143
No.1140-4/5
Continued from preceding page.
output will be omitted, since they are the same as those used in conventional quadrature detector ICs ( such as LA1230,
LA1231N).
The inverted output of the signal strength indication output is obtained as illustrated below.
By referring to the illustration, V14is given by the formula : V
14
=Vr–(I
0
+I
1
–aI
2
)R
L
–V
BE
.
Conditions are : Vr
≈
4.9V, I
0
≈
0.2mA, a
≈
2, R
L
=22k
, V
BE
≈
0.6V, I
1
=V
15
/R
15-G
,
I
2
=V
16
/R
16-G
, where V
16
is a constant equal to 4.1V (typ.) for medium or lower
signal input levels, where the muting drive output is required. Since the V
15
increases proportionally to the increase of the input signal strength, I1 will also
increase. Therefore the V
14
will decrease with increasing signal strength. Thus the
required muting drive output can be obtained by selecting proper values of R
15-G
and R
16-G
.
For example, the muting drive output moves toward strong input signal level if th R
16-G
is decreased, or the muting
drive output becomes zero due to the offset current I
O
under a weak signal input condition, if the R
16-G
is increased to
infinity (namely pin 16 is opened). However the muting drive output caused by a hole detector still exists in this case. In
creasing R
15-G
decreases the slope of the curve for the muting drive output vs. antenna signal input level, or decreasing
the R
15-G
increases the slope of the curve. Furthermore, varying the value of a resistor connected between the muting
drive output (pin 14) and the muting control input (pin 6) changes the value of the muting control current required to
obtain the same muting drive output, accordingly a slope of curve for muting attenuation vs. antenna signal input level is
also changed.
These characteristics investigated by using an actual receiver are shown on the curves below. The general method to
adjust the muting circuit of the LA1143 is : to set the signal input level required to actuate the muting circuit with the
R
16-G
, to adjust the slope of the curve for the muting attenuation vs. antenna signal input with the R
15-G
, and to adjust
the maximum muting attenuation (determined by setting the noise level at no signal) with the R
5-G
. The slope of the
curve for the muting attenuation vs. antenna signal input level can also be adjusted by the resistor connected between
pins 14 and 6 in addition to R
15-G
, however, selecting a resistor too high does not allow the muting control current
flowing into pin 6 to reach 120μA even though the maximum muting drive output (V
14
) is applied, namely the muting
attenuation does not reach its maximum value. Accordingly a recommended value of the resistor between pins 14 and 6
is about 22k
.
相關PDF資料 |
PDF描述 |
|---|---|
| LA1145 | FM IF System (Quadrature Detector) for Car Radio |
| LA1145M | FM IF System (Quadrature Detector) for Car Radio |
| LA1150N | FM IF Amplifier for Car Radio |
| LA1175 | FM Front End For Car Radio, Home Stereo Applications |
| LA1175M | FM Front End For Car Radio, Home Stereo Applications |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LA1145 | 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:FM IF System (Quadrature Detector) for Car Radio |
| LA1145M | 制造商:Panasonic Industrial Company 功能描述:IC |
| LA1145M-TLM-E | 功能描述:射頻接收器 CAR RADIO FM IF SYSTEM RoHS:否 制造商:Skyworks Solutions, Inc. 類型:GPS Receiver 封裝 / 箱體:QFN-24 工作頻率:4.092 MHz 工作電源電壓:3.3 V 封裝:Reel |
| LA1150 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC |
| LA1150N | 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:FM IF Amplifier for Car Radio |
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