|
|
PDF TEA0678 Data sheet ( Hoja de datos )
| Número de pieza | TEA0678 | |
| Descripción | Dual Dolby* B-type noise reduction circuit/ automatic music search/ with differential outputs and mute | |
| Fabricantes | NXP Semiconductors | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de TEA0678 (archivo pdf) en la parte inferior de esta página. Total 28 Páginas | ||
|
No Preview Available !
INTEGRATED CIRCUITS
DATA SHEET
TEA0678
Dual Dolby* B-type noise reduction
circuit, automatic music search,
with differential outputs and mute
Preliminary specification
Supersedes data of August 1993
File under Integrated Circuits, IC01
1996 Jun 06
1 page  
Philips Semiconductors
Dual Dolby* B-type noise reduction circuit, automatic
music search, with differential outputs and mute
Preliminary specification
TEA0678
FUNCTIONAL DESCRIPTION
Noise Reduction (NR) is enabled when pin NR/AMS is
connected to ground and disabled when open-circuit (left
floating from a 3-state output).
Dolby noise reduction only operates correctly if 0 dB Dolby
level is adjusted at 387.5 mV.
Automatic Music Search (AMS) is enabled when pin
NR/AMS is connected to HIGH (5 V) and disabled when
open-circuit (left floating from a 3-state output). In AMS
mode the signal of both channels are rectified and then
added. This means, even if one channel signal appears
inverted to the other channel, with the TEA0678 the normal
AMS function is ensured (see Figs 4, 5 and 6).
Equalization time constant switching (70 µs or 120 µs)
is achieved when pin AMSEQ is connected to GND via an
18 kΩ resistor (120 µs), or left open-circuit (70 µs).
This does not affect the AMS output signal during AMS
mode (see Fig.1).
Head switching is achieved when pin HS is connected to
GND (input IN1 active) or connected to HIGH (5 V) level
(input IN2 active). If left open-circuit IN1 is active.
Mute is enabled when pin MUTE is connected to ground
and off when connected to HIGH (5 V) level. For smooth
switching a time constant is recommended. If left
open-circuit MUTE is active.
The differential output stage of each channel is
connected via a provision to the Dolby and pre-amplifier
part. This provision may be used for any processing of the
tape signal or to add another signal. Each output drives a
resistive load of nominal 10 kΩ and is capable of driving
1 kΩ, also a capacitive load of 1.2 nF to ground and
between differential outputs. Each output can be
short-circuited to a battery (16 V) via a coupling capacitor
(4.7 µF).
LIMITING VALUES
In accordance with the Absolute Maximum Rating System (IEC 134); note1.
SYMBOL
PARAMETER
CONDITIONS MIN.
VCC
Vi
tshort
Tstg
Tamb
Ves
supply voltage
input voltage (pins 1 to 32) except pin 15 (Vref); pin 3
(NR/AMS), pin 18 (HS) and pin 30 (MUTE) to VCC
input voltage at pin 3 (NR/AMS), pin 18 (HS) and
pin 30 (MUTE)
note 2
pin 15 (Vref) to VCC short-circuiting duration
storage temperature
operating ambient temperature
electrostatic handling voltage for all pins
note 3
note 4
0
−0.3
−0.3
−
−55
−40
−2
−500
MAX.
16
+VCC
+6.5
5
+150
+85
+2
+500
UNIT
V
V
V
s
°C
°C
kV
V
Notes
1. The device may not operate correctly when subjected to these ratings when the ratings exceed the electrical
characteristics of the device as specified in Chapter “Characteristics”. The device will recover automatically when the
environment is reduced to the requirements of the characteristics.
2. The TEA0678 allows a HIGH-level at switching pins without supply voltage (VCC = 0; stand-by mode). This means a
maximum input voltage of 6.5 V for the switching input pins.
3. Human body model (1.5 kΩ, 100 pF).
4. Machine model (0 Ω, 200 pF).
1996 Jun 06
5
5 Page 
Philips Semiconductors
Dual Dolby* B-type noise reduction circuit, automatic
music search, with differential outputs and mute
Preliminary specification
TEA0678
Short description ‘music search’
A system for ‘music search’ mainly consists of a level and
a time detection (see Fig.4). For adapting and decoupling
the input signal will be amplified (A), then rectified (B) and
smoothed with a time constant (C). So the voltage at (C)
corresponds to the signal level and will be compared to the
predefined pause level at the first comparator (D), the level
detector. If the signal level becomes smaller than the
pause level, the level detector(D) changes its output
signal. Due to the output level of the level detector the
capacitor of the second time constant (E) will be charged,
respectively discharged. If the pause level of the input
signal remains for a certain time, the voltage at the
capacitor reaches a certain value, which corresponds to
an equivalent time value due to the charging. The voltage
at the capacitor will be compared to a predefined
time-equivalent voltage by the second comparator (F), the
time detector. If the pause level of the input signal remains
for this predefined time, the time detector (F) changes its
output level for ‘pause found’ status.
handbook, full pagewidth
(A)
INA
(B)
AMPLIFIER RECTIFIER
INB
(C) (D)
COMPARATOR 1
t1 VI
(E) (F)
COMPARATOR 2
t2 Vt
OUT
LEVEL DETECTOR
TIME DETECTOR
MED772
Fig.4 Integrated ‘music search’ function.
In this IC the signals of both channels are first rectified and then added. The signal behind the adder is described by
Vadd = VchanA + VchanB, where:
VchanA: absolute value channel A
VchanB: absolute value channel B
This means, even if one channel signal appears phase shifted to the other channel (at worst cases inverted), the
TEA0678 will ensure the normal AMS function.
1996 Jun 06
11
11 Page | ||
| Páginas | Total 28 Páginas | |
| PDF Descargar | [ Datasheet TEA0678.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| TEA0675 | Dual Dolby* B-type noise reduction circuit for playback applications | NXP Semiconductors |
| TEA0675T | Dual Dolby* B-type noise reduction circuit for playback applications | NXP Semiconductors |
| TEA0676 | Dual pre-amplifier and equalizer for reverse tape decks | NXP Semiconductors |
| TEA0676T | Dual pre-amplifier and equalizer for reverse tape decks | NXP Semiconductors |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |