LA1060 데이터 시트보기 (PDF) - SANYO -> Panasonic
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LA1060 Datasheet PDF : 8 Pages
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LA1060
Noise Detection Method of the LA1060
(1) "Count system"-used noise detection
• The LA 1060 is so designed as to count the noise components of 100kHz or greater in the IF output to detect the
multipath distortion.
• Car-use FM tuners are always affected by noises shown below.
(1) Ignition noise
(2) Noise attendant on modulation.
The actual modulation signal is not a continuous wave, but an intermittent signal. When the modulation signal
rises in a burst fashion, the high frequency noise components are detected in the FM demodulation output
(because in a burst fashion, overmodulation may occur or the signal rise characteristic may include the high
frequency components.)
(3) Random noise
The random noise at the weak input signal mode includes some noise components whose peak value is two to
three times as high as the average noise level.
• As a result of checking the above-mentioned noises, we found that the noise of more than a given level being
present within a given period of time (example : within 100µs) is included in the FM demodulation output of car-
use FM tuners at less than a given density only.
• By contrast, when the multipath distortion or skip noise occurs, the continuous noise components occur and the
above-mentioned noise density increases.
• Therefore, by using "count system" to count the noise density, the detection of multipath distortion and skip noise
detection can be performed with less malfunction.
(2) Noise detection time
• It is desirable that the noise detection time is faster (Note 1). However, the noise detection time (noise count time)
of the LA1060 is approximately 100µs so that the above-mentioned three types of noise cause no malfunction to
occur.
(Note 1) • If the period of noise duration is 20µs or less, the noise is hardly offensive to the ears. If the period of noise
duration is 50 to 200µs, the noise is heard as a sound "buzz", but a single noise is hardly offensive to the ears.
• If the period of noise duration is 500µs or more, the noise is heard as a sound "zah" which is offensive to the
ears.
Sample Application Circuit 2
Unit (resistance : Ω, capacitance : F)
No2650-5/8
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