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參數(shù)資料
| 型號(hào)： | TDA9888 |
| 廠商： | NXP Semiconductors N.V. |
| 英文描述： | DVB selective AGC amplifier |
| 中文描述： | AGC放大器的DVB選擇性 |
| 文件頁數(shù)： | 6/22頁 |
| 文件大小： | 136K |
| 代理商： | TDA9888 |
2004 Nov 02
6
Philips Semiconductors
Product specification
DVB selective AGC amplifier
TDA9888TS; TDA9889TS
Reference generation
The 4 MHz crystal is the reference for the downconversion
synthesizer and the filter synthesizer.
The downconverted DVB frequency and the frequency
adjustment of the integrated filters are dependent on the
precision of the reference signal at pin REF. An operation
as crystal oscillator is possible as well as connecting this
input via a serial capacitor to another low-ohmic reference
frequency source.
The integrated divider-by-8 generates the internally
needed 500 kHz reference frequency for the DVB
synthesizer and the reference filter.
Synthesizer for downconversion
The PLL synthesizer for downconversion consists of a
Voltage Controlled Oscillator (VCO), a divider with a
standard dependent divider factor, a frequency phase
detector (constructed as a digital 3-state comparator) and
a charge pump.
The VCO operates as an integrated low radiation
relaxation oscillator at double the conversion frequency.
For downconversion the VCO frequency is divided-by-2 to
provide two differential square wave signals with exactly
90 degrees phase difference, independent of the VCO
frequency.
Thefrequencyphasedetectorcomparesthedown-divided
oscillator signal with the 500 kHz reference frequency
signal and controls, via the charge pump, the control
voltage at the external loop filter connected to pin LFS,
which is required to tune the VCO exactly to the wanted
frequency.
The divider, the frequency phase detector and the
reference frequency divider are constructed in a low
radiation technique to optimize the synthesizer spurious
suppression in the downconverted output signal.
Downconversion and complex filtering
The gain controlled IF signal from the IF amplifier is fed to
two identical linear mixers, operating in the ‘in phase’ and
‘quadrature’ mode in accordance to the 0 and 90 degree
VCO signal from the synthesizer. With this, the
downconverted DVB low IF signal is available as an
I and Q signal in the frequency band from 1 to 9 MHz.
These signals are fed to the complex filter section. As a
result of adding both signals, the unwanted mirror signal
will be attenuated (approximately 34 dB). The unwanted
frequency components below 1 MHz are attenuated in a
high-pass filter. This signal is then fed through a
group-delay equalizer circuit.
Tracking low-pass filter with reference control
The low-pass filter is controlled by a reference signal
[generated by a frequency synthesizer and can be
switched by the standard selection (S0 and S1)].
The tracking low-pass filter is designed as a
Tschebyschefffiltertoguaranteesufficientsuppressionfor
the neighbouring picture carrier. An all-pass filter corrects
the characteristic to obtain a flat (equivalent ripple) group
delay behaviour.
Low IF differential output stage
The output amplifier consists of two identical differential
operational amplifiers with a high common mode (DC)
rejection ratio, to provide a constant DC voltage at the
output stage. The amplified Low IF (LIF) signal is available
as a differential signal with an amplitude of 2 V (p-p) and
DC level of 2 V (typ.) between the output terminals of both
amplifiers.
Logic control
The logic control provides an easy selection of the most
common standards for Europe, USA and Japan with the
two switches S0 and S1 (frequency selection different for
TDA9888TS and TDA9889TS) and controls all internal
standard dependent stages.
The five available tuner AGC modes can be set via the
3-state input pin S2 and R
TOP
connection (at pin TADJ).
Internal voltage stabilizer
The band gap circuit generates a voltage of approximately
2.4 V, independent of the supply voltage and the
temperature. A voltage regulator circuit, controlled by this
voltage, produces a constant voltage of 3.55 V which is
used as an internal reference voltage.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| TDA9889 | DVB selective AGC amplifier |
| TDA9889TS | DVB selective AGC amplifier |
| TDA9888TS | DVB selective AGC amplifier |
| TDA9901 | Wideband differential digital controlled variable gain amplifier(寬帶差分?jǐn)?shù)控可變?cè)鲆娣糯笃? |
| TDA9901TS | Wideband differential digital controlled variable gain amplifier |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| TDA9888TS | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:DVB selective AGC amplifier |
| TDA9889 | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:DVB selective AGC amplifier |
| TDA9889TS | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:DVB selective AGC amplifier |
| TDA9889TS/V1,512 | 功能描述:射頻放大器 DVB T AFRIC DOWN CONVERSION RoHS:否 制造商:Skyworks Solutions, Inc. 類型:Low Noise Amplifier 工作頻率:2.3 GHz to 2.8 GHz P1dB:18.5 dBm 輸出截獲點(diǎn):37.5 dBm 功率增益類型:32 dB 噪聲系數(shù):0.85 dB 工作電源電壓:5 V 電源電流:125 mA 測(cè)試頻率:2.6 GHz 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-16 封裝:Reel |
| TDA9889TS/V1,518 | 功能描述:射頻放大器 DVB T AFRIC DOWN CONVERSION RoHS:否 制造商:Skyworks Solutions, Inc. 類型:Low Noise Amplifier 工作頻率:2.3 GHz to 2.8 GHz P1dB:18.5 dBm 輸出截獲點(diǎn):37.5 dBm 功率增益類型:32 dB 噪聲系數(shù):0.85 dB 工作電源電壓:5 V 電源電流:125 mA 測(cè)試頻率:2.6 GHz 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-16 封裝:Reel |
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