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參數(shù)資料
| 型號： | TDA9855 |
| 廠商： | NXP SEMICONDUCTORS |
| 元件分類： | 消費家電 |
| 英文描述： | I2C-bus controlled BTSC stereo/SAP decoder and audio processor |
| 中文描述： | SPECIALTY CONSUMER CIRCUIT, PDIP52 |
| 封裝： | 0.600 INCH, PLASTIC, SOT-274-1, SDIP-52 |
| 文件頁數(shù)： | 10/52頁 |
| 文件大?。?/td> | 345K |
| 代理商： | TDA9855 |
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1997 Nov 04
10
Philips Semiconductors
Product specification
I
2
C-bus controlled BTSC stereo/SAP
decoder and audio processor
TDA9855
dbx
DECODER
The circuit includes all blocks required for the noise
reduction system in accordance with the BTSC system
specification. The output signal is fed through a 73
μ
s fixed
de-emphasis circuit to the dematrix block.
I
NTEGRATED FILTERS
The filter functions necessary for stereo and SAP
demodulation and part of the dbx filter circuits are provided
on-chip using transconductor circuits. The required filter
accuracy is attained by an automatic filter alignment
circuit.
Audio processor
S
ELECTOR
The selector allows selecting either the internal line out
signals LOR or LOL (dematrix output) or the external line
in signals LIR and LIL and combines the left and right
signals in several modes (see Table 12). The input signal
capability of the line inputs (LIR/LIL) is 2 V (RMS).
The output of the selector is AC-coupled to the automatic
volume level control circuit via pins SOR/SOL and
AVR/AVL to avoid offset voltages.
A
UTOMATIC VOLUME LEVEL CONTROL
The automatic volume level stage controls its output
voltage to a constant level of typically 200 mV (RMS) from
an input voltage range of 0.1 to 1.1 V (RMS). The circuit
adjusts variations in modulation during broadcasting and
due to changes in the programme material. The function
can be switched
off
. To avoid audible ‘plops’ during the
permanent operation of the AVL circuit a soft blending
scheme has been applied between the different gain
stages. A capacitor (4.7
μ
F) at pin C
AV
determines the
attack and decay time constants. In addition the ratio of
attack and decay time can be changed via the I
2
C-bus
(see notes 7 and 8 of Chapter “Characteristics”).
E
FFECTS
The audio processor section offers the following mode
selections: linear stereo, pseudo stereo, spatial stereo and
forced mono.The spatial mode provides an antiphase
crosstalk of 30% or 52% (switchable via the I
2
C-bus;
see Table 18).
V
OLUME
/
LOUDNESS
The volume control range is from +16 dB to
71 dB in
steps of 1 dB and ends with a mute step (see Table 8).
Balance control is achieved by the independent volume
control of each channel. The volume control blocks
operate in combination with the loudness control. The filter
is linear when maximum gain for volume control is
selected. The filter characteristic changes automatically
over a range of 28 dB down to a setting of
12 dB.
At
12 dB volume control the maximum loudness boost is
obtained. The filter characteristic is determined by external
components. The proposed application provides a
maximum boost of 17 dB for bass and 4.5 dB for treble.
The loudness may be switched
on
or
off
via I
2
C-bus
control (see Table 14). The left and right volume control
stages include two independent zero-crossing detectors.
In the zero-crossing mode a change in volume is
automatically activated but not executed. The execution is
enabled at the next zero-crossing of the signal. If a new
volume step is activated before the previous one has been
processed, the previous value will be executed first, and
then the new value will be activated. If no zero-crossing
occurs the next volume transmission will enforce the last
activated volume setting.
The zero-crossing mode is realized between adjoining
steps and between any steps, but not from any step to
mute. In this case the GMU bit is required for use. In case
only one channel has to be muted, two steps are
necessary. The first step is a transmission of any step to
71 dB and the second step is the
71 dB step to mute
mode. The step of
71 dB to mute mode has no
zero-crossing but this is not relevant. This procedure has
to be provided by software.
B
ASS CONTROL
A single external 33 nF capacitor for each channel in
combination with a linear operational amplifier and internal
resistors provides a bass control range of +16.5 to
12 dB
in steps of 1.5 dB at low frequencies (40 Hz). Internally the
basic step width is 3 dB, with intermediate steps obtained
by a toggle function that provides an additional 1.5 dB
boost or attenuation (see Table 9). It should be noted that
both loudness and bass control together result in a
maximum bass boost of 34.5 dB for low volume steps.
T
REBLE CONTROL
The adjustable range of the treble control stage is from
12 to +12 dB in steps of 3 dB. The filter characteristic is
determined by an external 5.6 nF capacitor for each
channel. The logic circuitry is arranged in a way that the
same data words (06H to 16H) can be used for both tone
controls if a bass control range from
12 to +12 dB and a
treble control range from
12 to +12 dB with 3 dB steps
are used (see Tables 9 and 10).
相關PDF資料 |
PDF描述 |
|---|---|
| TDA9855WP | I2C-bus controlled BTSC stereo/SAP decoder and audio processor |
| TDA9859 | Universal hi-fi audio processor for TV |
| TDA9860 | Universal HiFi audio processor for TV |
| TDA9861 | Universal HiFi audio processor for TV |
| TDA9873 | Multistandard dual carrier stereo sound decoder |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| TDA9855/V2,112 | 功能描述:音頻放大器 BTSC STEREO DECODER RoHS:否 制造商:STMicroelectronics 產品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel |
| TDA9855N | 功能描述:音頻放大器 BTSC STEREO DECODER DBXTV/AUD RoHS:否 制造商:STMicroelectronics 產品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel |
| TDA9855WP | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:I2C-bus controlled BTSC stereo/SAP decoder and audio processor |
| TDA9859 | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Universal hi-fi audio processor for TV |
| TDA9859H | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Universal hi-fi audio processor for TV |
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