參數(shù)資料
型號(hào)： TDA9884HN
廠商： NXP SEMICONDUCTORS
元件分類： 接收器
英文描述： AM/FM, AUDIO/VIDEO DEMODULATOR, PQCC32
封裝： 5 X 5 MM, 0.85 MM HEIGHT, PLASTIC, MO-220, HVQFN-32
文件頁(yè)數(shù)： 58/58頁(yè)
文件大?。?/td> 290K
代理商： TDA9884HN
TDA9884_2
Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Product data sheet
Rev. 02 — 12 May 2006
9 of 58
Philips Semiconductors
TDA9884
I2C-bus controlled multistandard alignment-free IF-PLL
very long time constant for VIF gain increase is because the peak white level may appear
only once in a eld. In order to reduce this time constant, an additional level detector
increases the discharging current of the AGC capacitor (fast mode) in the event of a
decreasing VIF amplitude step controlled by the detected actual black level voltage. The
threshold level for fast mode AGC is typically
6 dB video amplitude. The fast mode state
is also transferred to the SIF-AGC detector for speed-up. In case of missing peak white
pulses, the VIF gain increase is limited to typically +3 dB by comparing the detected
actual black level voltage with a corresponding reference voltage.
7.4 FPLL detector
The VIF amplier output signal is fed into a frequency detector and into a phase detector
via a limiting amplier for removing the video AM.
During acquisition the frequency detector produces a current proportional to the
frequency difference between the VIF and the VCO signals. After frequency lock-in the
phase detector produces a current proportional to the phase difference between the VIF
and the VCO signals. The currents from the frequency and phase detectors are charged
into the loop lter which controls the VIF VCO and locks it to the frequency and phase of
the VIF carrier.
For a positive modulated VIF signal, the charging currents are gated by the composite
sync in order to avoid signal distortion in case of overmodulation. The gating depth is
switchable via the I2C-bus.
7.5 VCO and divider
The VCO of the VIF-FPLL operates as an integrated low radiation relaxation oscillator at
double the picture carrier frequency. The control voltage, required to tune the VCO to
double the picture carrier frequency, is generated at the loop lter by the frequency phase
detector. The possible frequency range is 50 MHz to 140 MHz (typical value).
The oscillator frequency is divided-by-two to provide two differential square wave signals
with exactly 90 degrees phase difference, independent of the frequency, for use in the
FPLL detectors, the video demodulator and the intercarrier mixer.
7.6 AFC and digital acquisition help
Each relaxation oscillator of the VIF-PLL and FM-PLL demodulator has a wide frequency
range. To prevent false locking of the PLLs and with respect to the catching range, the
digital acquisition help provides an individual control, until the frequency of the VCO is
within the preselected standard dependent lock-in window of the PLL.
The in-window and out-window control at the FM-PLL is additionally used to mute the
audio stage (if auto mute is selected via the I2C-bus).
The working principle of the digital acquisition help is as follows. The PLL VCO output is
connected to a down counter which has a predened start value (standard dependent).
The VCO frequency clocks the down counter for a xed gate time. Thereafter, the down
counter stop value is analyzed. In case the stop value is higher (lower) than the expected
value range, the VCO frequency is lower (higher) than the wanted lock-in window
frequency range. A positive (negative) control current is injected into the PLL loop lter
and consequently the VCO frequency is increased (decreased) and a new counting cycle
starts.
相關(guān)PDF資料
PDF描述
TDA9885HN/V5 AM/FM, AUDIO/VIDEO DEMODULATOR, PQCC32
TDA9885T/V5 AM/FM, AUDIO/VIDEO DEMODULATOR, PDSO24
TDA9885TS/V5 AM/FM, AUDIO/VIDEO DEMODULATOR, PDSO24
TDA9886HN/V5 AM/FM, AUDIO/VIDEO DEMODULATOR, PQCC32
TDA9886T/V5 AM/FM, AUDIO/VIDEO DEMODULATOR, PDSO24
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TDA9884TS 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:I2C-bus controlled multistandard alignment-free IF-PLL for mobile reception
TDA9884TS/V1 功能描述:調(diào)節(jié)器/解調(diào)器 MOBILE VIF AND SIF DEMODULATOR RoHS:否 制造商:Texas Instruments 封裝 / 箱體:PVQFN-N24 封裝:Reel
TDA9884TS/V1,112 功能描述:調(diào)節(jié)器/解調(diào)器 MOBILE VIF AND SIF RoHS:否 制造商:Texas Instruments 封裝 / 箱體:PVQFN-N24 封裝:Reel
TDA9884TS/V1,118 功能描述:調(diào)節(jié)器/解調(diào)器 MOBILE VIF AND SIF RoHS:否 制造商:Texas Instruments 封裝 / 箱體:PVQFN-N24 封裝:Reel
TDA9884TS/V1/S1,11 功能描述:調(diào)節(jié)器/解調(diào)器 MOBILE VIF AND SIF RoHS:否 制造商:Texas Instruments 封裝 / 箱體:PVQFN-N24 封裝:Reel
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