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參數(shù)資料
| 型號： | U4080B |
| 英文描述： | Voice-Switched Circuit for Handsfree Operation |
| 中文描述： | 語音電路交換的免提操作 |
| 文件頁數(shù)： | 6/15頁 |
| 文件大?。?/td> | 169K |
| 代理商： | U4080B |
U4080B
TELEFUNKEN Semiconductors
Rev. A1, 20-May-96
Preliminary Information
6 (15)
Transmit and Receive Attenuators
The transmit and receive attenuators are supplementary
in function. This means that when one is at maximum
gain, the other is at maximum attenuation, and vice versa.
That is, both are never on or off. They are controlled by
the voltage of ACF (attenuator control filter) at Pin 25
being supplied by attenuator control as shown in figure 1
The ACF voltage is provided by the attenuator control
block, which receives the three inputs given below:
R-T comparator
Transmit detector comparator
Volume control
The response of the attenuators is based on the difference
between the ACF voltage and V
CC
. If the difference
( V
ACF
) is
6 mV, the transmit attenuator is fully on and
the receive attenuator is fully off (T mode). If V
ACF
150 mV, the circuit is in the R mode. If V
ACF
the circuit is in the idle mode, and the two attenuators are
at gain settings approximately half way (in dB) between
their fully on and fully off positions.
75 mV,
Three resistors R
1
, RTG and RD, determine maximum
gain and attenuation values. R
1
effects both attenuators
according to its value relative to RTG and RG. Figure 4
shows the variations versus the ratio of other resistors to
R1. RTG affects the gain and attenuation of only the
transmit attenuator according to the curves of figure 2,
while RG affects only the receive attenuator according to
figure 3 Gain difference from on to off, according to the
figures, is a reasonably constant 45 dB until the upper
gain limit is approached. A value of R1 = 30 k
is recom-
mended as a starting point, and then the values of RTG
and RG selected to suit the particular design goals.
The input impedance of the attenuators (at TI and RECI)
is typically 5.0 k
, and the maximum input signal which
will not cause output distortion is 250 mV
rms
(707 mV
pp
).
The 4 k
resistor and 0.01
μ
F capacitor at RECO (in
figure 1) filters out high-frequency components in the
receive path. This helps to minimize high-frequency
acoustic feedback problems which may occur if the filter
were not present.
The filter’s insertion loss is 1.5 dB at 1.0 kHz. The outputs
of the attenuators are inverted from their inputs. Referring
to the attenuator control block, the V
ACF
voltage at its
output is determined by three inputs.
The relationship of
the inputs and outputs is summarized in the following
truth table:
Transmit
T-R
Det
Volume
V
ACF
Mode
Comp
Transmit
Transmit
Receive
Receive
Comp
Transmit
Idle
Transmit
Idle
Control
No Effect
No Effect
Affects V
ACF
Affects V
ACF
6.0 mV
75.0 mV
50 – 150 mV
50 – 150 mV
Transmit
Idle
Receive
Receive
RG (k
0
100
–40
–20
0
20
1000
VR
ACF
= 8 mV
VR
ACF
= 150 mV
94 7864 e
G
R
Figure 2.
0
100
40
20
0
20
G
T
RTG (k
1000
VT
ACF
= 8 mV
VT
ACF
= 150 mV
94 7863 e
Figure 3.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| U4082B | 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:Low-voltage Voice-switched IC for Hands-free Operation |
| U4082B-DEV-BOARD | 功能描述:射頻開發(fā)工具 Voice Switched Circuit RoHS:否 制造商:Taiyo Yuden 產(chǎn)品:Wireless Modules 類型:Wireless Audio 工具用于評估:WYSAAVDX7 頻率: 工作電源電壓:3.4 V to 5.5 V |
| U4082B-MFLG | 功能描述:射頻無線雜項(xiàng) COM.CORDED - VOICE SWITCHED CIRCUIT RoHS:否 制造商:Texas Instruments 工作頻率:112 kHz to 205 kHz 電源電壓-最大:3.6 V 電源電壓-最小:3 V 電源電流:8 mA 最大功率耗散: 工作溫度范圍:- 40 C to + 110 C 封裝 / 箱體:VQFN-48 封裝:Reel |
| U4082B-MFLG3G | 功能描述:射頻無線雜項(xiàng) COM.CORDED - VOICE SWITCHED CIRCUIT RoHS:否 制造商:Texas Instruments 工作頻率:112 kHz to 205 kHz 電源電壓-最大:3.6 V 電源電壓-最小:3 V 電源電流:8 mA 最大功率耗散: 工作溫度范圍:- 40 C to + 110 C 封裝 / 箱體:VQFN-48 封裝:Reel |
| U4083 | 制造商:TEMIC 制造商全稱:TEMIC Semiconductors 功能描述:Low-Power Audio Amplifier for Telephone Applications |
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