參數(shù)資料
型號(hào)： TDA9818
廠(chǎng)商： NXP SEMICONDUCTORS
元件分類(lèi)： 接收器
英文描述： Single/Multistandard VIF/SIF-PLL and FM-PLL/AM demodulator(單一/多標(biāo)準(zhǔn)的VIF/SIF-PLL and FM-PLL/AM解調(diào)器)
中文描述： AM/FM, AUDIO/VIDEO DEMODULATOR, PDIP24
封裝： 0.400 INCH, PLASTIC, SOT-234-1, SDIP-24
文件頁(yè)數(shù)： 6/36頁(yè)
文件大小： 163K
代理商： TDA9818
1997 May 12
6
Philips Semiconductors
Preliminary specification
Single/multistandard VIF/SIF-PLL and
FM-PLL/AM demodulators
TDA9817; TDA9818
FUNCTIONAL DESCRIPTION
The integrated circuit comprises the functional blocks as
shown in Fig.1:
Vision IF amplifier and VIF AGC detector
Tuner AGC
Frequency Phase Locked Loop detector (FPLL)
VCO, Travelling Wave Divider (TWD) and AFC
Video demodulator and amplifier
SIF amplifier and SIF AGC
Single reference QSS mixer
AM demodulator
FM-PLL demodulator
AF (Audio Frequency) signal processing
Internal voltage stabilizer.
Vision IF amplifier and VIF AGC detector
The vision IF amplifier consists of three AC-coupled
differential amplifier stages. Each differential stage
comprises a feedback network controlled by emitter
degeneration.
The AGC detector generates the required VIF gain control
voltage for constant video output by charging/discharging
the AGC capacitor. Therefore for negative video
modulation the sync level and for positive video
modulation the peak white level of the video signal is
detected. In order to reduce the reaction time for positive
modulation, where a very large time constant is needed,
an additional level detector increases the discharging
current of the AGC capacitor (fast mode) in the event of a
decreasing VIF amplitude step. The additional level
information is given by the black-level detector voltage.
Tuner AGC
The AGC capacitor voltage is converted to an internal IF
control signal, and is fed to the tuner AGC to generate the
tuner AGC output current at pin TAGC (open-collector
output). The tuner AGC takeover point can be adjusted at
pin TADJ. This allows to match the tuner to the SAW filter
in order to achieve the optimum IF input level.
Frequency Phase Locked Loop detector (FPLL)
The VIF-amplifier output signal is fed into a frequency
detector and into a phase detector via a limiting amplifier.
During acquisition the frequency detector produces a DC
current proportional to the frequency difference between
the input and the VCO signal. After frequency lock-in the
phase detector produces a DC current proportional to the
phase difference between the VCO and the input signal.
The DC current of either frequency detector or phase
detector is converted into a DC voltage via the loop filter,
which controls the VCO frequency. In the event of positive
modulated signals the phase detector is gated by
composite sync in order to avoid signal distortion for
overmodulated VIF signals.
VCO, Travelling Wave Divider (TWD) and AFC
The VCO operates with a resonance circuit (with L and C
in parallel) at double the PC frequency. The VCO is
controlled by two integrated variable capacitors.
The control voltage required to tune the VCO from its
free-running frequency to actually double the PC
frequency is generated by the frequency-phase detector
(FPLL) and fed via the loop filter to the first variable
capacitor. This control voltage is amplified and additionally
converted into a current which represents the AFC output
signal. At centre frequency the AFC output current is equal
to zero.
For TDA9818: the VCO centre frequency can be
decreased (required for L accent standard) by activating
an additional internal capacitor. This is achieved by using
the L accent switch. In this event the second variable
capacitor can be controlled by a variable resistor at the L
accent switch for setting the VCO centre frequency to the
required L accent value.
The oscillator signal is divided by 2 with a TWD which
generates two differential output signals with a 90 degree
phase difference independent of the frequency.
Video demodulator and amplifier
The video demodulator is realized by a multiplier which is
designed for low distortion and large bandwidth. The vision
IF input signal is multiplied with the ‘in phase’ signal of the
travelling wave divider output. In the demodulator stage
the video signal polarity can be switched in accordance
with the TV standard.
The demodulator output signal is fed via an integrated
low-pass filter for attenuation of the carrier harmonics to
the video amplifier. The video amplifier is realized by an
operational amplifier with internal feedback and high
bandwidth. A low-pass filter is integrated to achieve an
attenuation of the carrier harmonics for B/G and
L standard. The standard dependent level shift in this
stage delivers the same sync level for positive and
negative modulation. The video output signal at V
o(vid)
is
1.1 V (p-p) for nominal vision IF modulation, in order to
achieve 1 V (p-p) at sound trap output.
相關(guān)PDF資料
PDF描述
TDA9818T Single/multistandard VIF/SIF-PLL and FM-PLL/AM demodulators
TDA9817TS Single/multistandard VIF/SIF-PLL and FM-PLL/AM demodulators
TDA9817T Single/multistandard VIF/SIF-PLL and FM-PLL/AM demodulators
TDA9818TS Single/multistandard VIF/SIF-PLL and FM-PLL/AM demodulators
TDA9819T Multistandard vision and sound-IF PLL with DVB-IF processing
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TDA9818T 制造商:PHILIPS 制造商全稱(chēng):NXP Semiconductors 功能描述:Single/multistandard VIF/SIF-PLL and FM-PLL/AM demodulators
TDA9818T/V1,118 功能描述:IC FM-PLL/AM DEMOD 24-SOIC RoHS:是 類(lèi)別:集成電路 (IC) >> 線(xiàn)性 - 視頻處理 系列:- 產(chǎn)品變化通告:Product Discontinuation 07/Mar/2011 標(biāo)準(zhǔn)包裝:3,000 系列:OMNITUNE™ 類(lèi)型:調(diào)諧器 應(yīng)用:移動(dòng)電話(huà)，手機(jī)，視頻顯示器 安裝類(lèi)型:表面貼裝 封裝/外殼:65-WFBGA 供應(yīng)商設(shè)備封裝:PG-WFSGA-65 包裝:帶卷 (TR) 其它名稱(chēng):SP000365064
TDA9818TS 制造商:PHILIPS 制造商全稱(chēng):NXP Semiconductors 功能描述:Single/multistandard VIF/SIF-PLL and FM-PLL/AM demodulators
TDA9819 制造商:PHILIPS 制造商全稱(chēng):NXP Semiconductors 功能描述:Multistandard vision and sound-IF PLL with DVB-IF processing
TDA9819T 制造商:PHILIPS 制造商全稱(chēng):NXP Semiconductors 功能描述:Multistandard vision and sound-IF PLL with DVB-IF processing
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