參數(shù)資料
型號: LA75501
廠商: SANYO SEMICONDUCTOR CO LTD
元件分類: 接收器
英文描述: AM/FM, AUDIO/VIDEO DEMODULATOR, PDIP24
封裝: 0.300 INCH, DIP-24
文件頁數(shù): 10/11頁
文件大小: 112K
代理商: LA75501
If this phase distortion (
θ) appears, the PLL VCO will be modulated in synchronization with the error voltage, which causes the
generation of a buzz. At Sanyo, this buzz generated by the phase distortion (
θ) is called ‘‘Nyquist buzz.’’ The LA7578N includes a
new Nyquist buzz canceller circuit that suppresses this Nyquist buzz generated by the phase distortion (
θ) in an effort to greatly
improve the buzz characteristics. Fig. 3 shows the PLL detection system in the LA7578N, which uses this Nyquist buzz canceller
circuit.
Fig. 3 PLL Detector with Nyquist Buzz Canceller
In the PLL detection system with the Nyquist buzz canceller, even if phase distortion such as that shown in A is generated, the
phase distortion in the APC detection output can be eliminated by generating and adding in a quasi-reverse phase buzz signal.
Nyquist buzz
Quasi-reverse phase buzz
Fig. 4 Nyquist Buzz Canceller Waveforms
The effect of this Nyquist buzz canceller circuit is to broadly suppress the buzz (fH harmonic ) generated as a sideband of the SIF
beat signal (4.5 MHz). As a result, great improvements can be made in regard to the buzz beat generated during demodulation of
Japan audio multiplexing (L-R) and the buzz characteristics during demodulation of U.S. MTS (Multichannel TV Sound) (L-R).
Furthermore, because this Nyquist buzz cancellation method has no effect on the time constant of the PLL loop, it is also possible
to try to improve various characteristics, by making it possible to, for example, design an APC filter that is not readily affected by
flyback pulses (F.B.P), etc.
LA7578N
No.4952-8/18
相關(guān)PDF資料
PDF描述
LA75503V AM/FM, AUDIO/VIDEO DEMODULATOR, PDSO30
LA75503V AM/FM, AUDIO/VIDEO DEMODULATOR, PDSO30
LA75505M AM/FM, AUDIO/VIDEO DEMODULATOR, PDSO24
LA75520KVA AM/FM, AUDIO/VIDEO DEMODULATOR, PDSO24
LA75520KVA AM/FM, AUDIO/VIDEO DEMODULATOR, PDSO24
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LA75501V 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:For Use in TV/VTR Applications VIF/SIF Signal Processing IC
LA75501V_07 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:For Use in TV/VTR Applications VIF/SIF Signal Processing IC
LA75503V 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:Adjustment Free VIF/SIF Signal Processing IC for PAL TV/VCR
LA75503V_07 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:For PAL TV/VCR Adjustment Free VIF/SIF Signal Processing IC
LA75505M 制造商:未知廠家 制造商全稱:未知廠家 功能描述: