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參數(shù)資料
| 型號(hào)： | LA3370 |
| 元件分類： | 接收器 |
| 英文描述： | FM, AUDIO DEMODULATOR, PZIP16 |
| 封裝： | 3 MM PITCH, SIP-16 |
| 文件頁(yè)數(shù)： | 7/11頁(yè) |
| 文件大?。?/td> | 175K |
| 代理商： | LA3370 |
LA3370
No.619-5/11
(2) Designing external circuits for SNC characteristics (characteristic setting by drawing)
We recommend the following as a way to adjust SNC characteristics to have smooth transition of separation from
stereo monaural in region A of Fig.2.
Separation vs. S/N enhancement relation...................................Refer to Fig.3.
SNC pin voltage vs.separation characteristics............................Refer to Fig.4.
Antenna inputs vs. S/N improvement characteristics can be obtained from the drawing if the graph for IF stage signal
meter output vs. antenna input and the graph for stereo S/N ratio vs. antenna input are known. From desired S/ N
characteristics, SNC terminal voltage characteristics can also be obtained. Sample drawings are shown in Fig.6, where
for simplicity's sake, SNC, IF meter, and stereo S/N characteristics have been approximated with straight lines.
For instance :
To obtain stereo S/N improvement characteristics from SNC characteristics, when (a) in the second quadrant of
the chart represents bare SNC characteristics, point 1 projected to the third quadrant shows a 20dB separation and
a 1dB S/N improvement. When projected from the first to the fourth quadrant, a point improved by 1dB in S/N
over the stereo S/N line in the fourth quadrant corresponds to point 1. Similarly, point 2 on the SNC characteristics
in the second quadrant corresponds to point 2 in the fourth quadrant. Point 3 in the second quadrant corresponds to
point 3 in the fourth quadrant. Stereo S/ N improvement characteristics for each point are obtainable. Similarly,
(b) characteristics in the second quadrant are projected to form (b) characteristics in the fourth quadrant, and (c) in
the second quadrant to form (c) in the fourth quadrant, thus providing a way to diagram improvement
characteristics.
In the resulting drawings, ideal S/N improvement characteristics are similar to (b) in the fourth quadrant, but
corresponding SNC characteristics have to be (b) characteristics in the second quadrant which are difficult to realize.
Among realistic characteristics, something like (c) appears to be satisfactory. The (c) SNC characteristics are obtained
with a shift by two diodes together with a 1/ 2 bleeder.
(3) HCC (high-cut control)
In region B where S/N deteriorates to 40dB or worse even for monaural, the S/N as sensed by the human ear can be
enhanced by suppressing levels at frequencies above approximately 7kHz. Treble region levels that follow meter
voltages can be smoothly attenuated (high-cut control) by impressing IF stage signal meter output to the HCC pin
(pin7) of the LA3370. Fig.7 shows MPX output frequency characteristics (monaural) provided by voltage impressed
on pin 7. Frequency characteristics for a 100% high cut can be determined by an external capacitor connected to pin 4.
An equivalent circuit is shown below where the designation is made by the 5k
Ω and the C time constant.
Approximate values provided by C as expressed in attenuation at 10kHz are listed in table below : right.
C [
μF]
Attenuation at 10kHz (dB)
0.01
-11
0.033
-21
0.047
-25
4
5k
Ω
LA3370
C
To decoder
Input
0.068
-28
Fig. 8 shows the relation between voltages impressed on pin 7 and rates (%) of high cut (HCC). When IF meter output
voltage characteristics and region B, S/N characteristics, of Fig. 2 have been obtained, S/N improvement by HCC can
be drawn in a way similar to drawing SNC chracteristics.
Fig.2 shows typical meter outputs of a quadrature detection IF amplifier IC. (Fig. 1 shows data for LA1140) HCC
characteristics have been designated to permit region B improvements when the IC is directly connected to HCC
(pin 7) terminal of the LA3370. The infinitesimal control currents at pin 7, similar to pin 8, do not affect meter outputs.
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| LA3373 | FM, AUDIO DEMODULATOR, PDIP16 |
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| LA3376 | SPECIALTY CONSUMER CIRCUIT, PZIP16 |
| LA3401 | AM/FM, AUDIO DEMODULATOR, PDIP22 |
| LA3410 | FM, AUDIO DEMODULATOR, PDIP16 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LA3370-E | 制造商:Sony Semiconductor Solutions Division 功能描述: |
| LA3373 | 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:PLL MULTIPLEX STEREO DEMODULATOR |
| LA3375 | 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:Pilot Cancel-Provided PLL FM MPX Demodulator for Car Stereos |
| LA3376 | 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:Pilot Cancel-Provided PLL FM MPX Demodulator for Car Stereos |
| LA3376M | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Consumer IC |
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