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参数资料
| 型号： | PBL388131N |
| 厂商： | ERICSSON |
| 英文描述： | Voice-switched Speakerphone Circuit with built in loudspeaker amplifier |
| 中文描述： | 语音交换与内置免提扬声器放大器电路 |
| 文件页数： | 11/16页 |
| 文件大小： | 299K |
| 代理商： | PBL388131N |
11
PBL 388 13
Figure 23. Loudspeaker amplifier current supply system.
PBL
388 13
19
+
This resistor sets
the max. attenuation
This resistor sets
the min. attenuation
position on the pot.
a).
PBL
388 13
19
+
Weighted
resistors
Three bit
digital
signal
b).
Some optional features using
the dc. set volume control on
the loudspeaker amplifier of
PBL 388 13.
The DC set volume control has an
wholly internal function to lower the gain at
low supply voltages. This is to avoid that
the power stage dies and causes breaks in
the output signal at long line lengths ie. low
currents in combination with high input
signals. This DC controlled volume is
externally accessible in the PBL 388 13
and can thus be utilized in several ways.
Figure 24. DC - volume control options.
a). To control the loudspeaker volume
with a DC- voltage from a potentiometer.
b). To control the loudspeaker volume
with a digital signal ( for ex. 8 - levels ).
c). An AGC can be combined with the
volume control by connecting a resistor
from the DC - control pin 19 to the output of
the receiver detector at pin 9. Care has to
be taken not to disturb the speech switching
balance. If the resistor is made too low
ohmic the same value has to be applied on
the transmitter detector output at pin 6 as
well as that the capacitors at the detector
outputs have to be made bigger.
d). A ”softclipping” with a fixed level
can be combined with the volume control.
A draw back with the fixed level is that
when setting it in to inhibit clipping distortion
at a long line ie. low level, the level will not
increase with short lines even if the supply
voltage would allow it. In the other case
when setting the level for a short line some
amplitude clipping on long line can be
expected.
e). A ”softclipping” that is controlled by
the ”real” output level that means that the
"softclipping" will follow the line current
changes and will at all times give the opti-
mum distortion limiting performance.
PBL
388 13
19
To volume
control
Resistor that is added
and which determines
the dynamics of the AGC
9
c).
PBL
388 13
19
To volum
control
Resistor that sets the
"softclipping" level
11
+
+
10
μ
F
pin 4
d).
PBL
388 13
20
To volume
control
19
+
10
μ
F
18
17
Sets the steepness
of the "softclipping"
Resistor that sets the
"softclipping" level
e).
Figure 25. DC - volume control options.
+
-
V
s
2,6V
Level shift
PBL 388 13
16
23
audio input
+ Line
- Line
I
L
20
2V DC-
supply
+
C
+
18
17
22
21
R
E
V
RE
V
R
Z
≈
0
I
B
R
I
R
2
Speech IC
I
C
1
-
+
V
RE
= V ;
V
R
= I
R x
R;
V
S
= 0 then I
C
= 0
I
C
< 50
I = 50
= 50
I
R
x
x
x
x
T
X
from Rx
channel
V
c
I
E
R
R
E
V
R
R
E
19
I
L
= I
R
= I
B
+ I
C
;
相关PDF资料 |
PDF描述 |
|---|---|
| PBL388131SO | Voice-switched Speakerphone Circuit with built in loudspeaker amplifier |
| PBL38814 | Voice - switched 2-channel Circuit with loudspeaker amplifier |
| PBL388141N | Voice - switched 2-channel Circuit with loudspeaker amplifier |
| PBL388141SO | Voice - switched 2-channel Circuit with loudspeaker amplifier |
| PBL388141SOT | Voice - switched 2-channel Circuit with loudspeaker amplifier |
相关代理商/技术参数 |
参数描述 |
|---|---|
| PBL388131SO | 制造商:ERICSSON 制造商全称:Ericsson 功能描述:Voice-switched Speakerphone Circuit with built in loudspeaker amplifier |
| PBL388131SOT | 制造商:ERICSSON 制造商全称:Ericsson 功能描述:Voice-switched Speakerphone Circuit with built in loudspeaker amplifier |
| PBL38814 | 制造商:ERICSSON 制造商全称:Ericsson 功能描述:Voice - switched 2-channel Circuit with loudspeaker amplifier |
| PBL388141N | 制造商:ERICSSON 制造商全称:Ericsson 功能描述:Voice - switched 2-channel Circuit with loudspeaker amplifier |
| PBL388141SO | 制造商:ERICSSON 制造商全称:Ericsson 功能描述:Voice - switched 2-channel Circuit with loudspeaker amplifier |
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