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參數(shù)資料
| 型號： | 73K321L-IP |
| 廠商： | TDK Corporation |
| 英文描述： | CCITT V.23, V.21 Single-Chip Modem |
| 中文描述： | 國際電話電報諮詢委員會.23，.21單芯片調(diào)制解調(diào)器 |
| 文件頁數(shù)： | 20/24頁 |
| 文件大小： | 140K |
| 代理商： | 73K321L-IP |
73K321L
CCITT V.23, V.21
Single-Chip
20
DIRECT ACCESS ARRANGEMENT (DAA)
The telephone line interfaces show two examples of
how the “hybrid” may be implemented. The split
supply design (Figure 1) is a typical two op-amp
hybrid. The receive op-amp serves two purposes. It
supplies gain to amplify the receive signal to the
proper level for the modem’s detectors and
demodulator, and it removes the transmitted signal
from the receive signal present at the transformer.
This is done by supplying a portion of the
transmitted signal to the non-inverting input of the
receive op-amp at the same amplitude as the signal
appearing at the transformer, making the transmit
signal Common mode.
The single-supply hybrid is more complex than the
dual-supply version described above, but its use
eliminates the need for a second power supply. This
circuit (Figure 2) uses a bridged drive to allow
undistorted signals to be sent with a single 5V
supply.
Because DTMF tones utilize a higher amplitude than
data, these signals will clip if a single-ended drive
approach is used. The bridged driver uses an extra
op-amp (U1A) to invert the signal coming from the
gain setting op-amp (U1B) before sending it to the
other leg of the transformer. Each op-amp then
supplies half the drive signal to the transformer. The
receive amplifier (U1C) picks off its signal at the
junction of the impedance matching resistor and the
transformer. Because the bottom leg of the
transformer is being driven in one direction by U1A
and the resistor is driven in the opposite direction at
the same time by U1B, the junction of the
transformer and resistor remains relatively constant
and the receive signal is unaffected.
DESIGN CONSIDERATIONS
TDK Semiconductor's 1-chip modem products
include all basic modem functions. This makes these
devices adaptable for use in a variety of
applications, and as easy to control as conventional
digital bus peripherals.
FIGURE 2: Single 5V Hybrid Version
RXA
-
+
R4
37.4K 1%
C1
390 pF
TXA
C10
0.47 μF
250V
D1
IN4004
R12
22K
T1
MIDCOM
VR1
VMOV
T
R
U2
4N35
U1C
*
2R2
C6
0.1 μF
+5V
+
-
U1B
*
+5V
K1
D4
IN914
2N2222A
Q1
R14
10K
10
9
8
R1
20K 1%
R3
475 1%
7
6
5
4
11
R5 3.3K
C4
0.0047 μF
R6
22.1K
R7
20K 1%
C3
0.1 μF
C5
750 pF
R9
20K 1%
R8
20K 1%
-
+
U1A
*
1
3
2
C2
0.033 μF
3.3V
ZENERS
D2
D3
+5V
R13
22K
+5V
C7
0.1 μF
C8
10 μF
HOOK
RING
VOLTAGE
REFERENCE
R10
*
R11
*
+
* Note: Op-amp U1
must be rated for
single 5V operation.
R10 & R11 values
depend on Op-amp
used.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| 73K321L | Miniature Switch, High Precision |
| 73K322L-IH | CCITT V.23, V.22, V.21 Single-Chip Modem |
| 73K322L-IP | CCITT V.23, V.22, V.21 Single-Chip Modem |
| 73K322L | CCITT V.23, V.22, V.21 Single-Chip Modem(CCITT V.23, V.22, V.21單片Modem) |
| 73M223 | 1200 Baud FSK Modem |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| 73K322L | 制造商:TDK 制造商全稱:TDK Electronics 功能描述:CCITT V.23, V.22, V.21 Single-Chip Modem |
| 73K322L-IH | 制造商:TDK 制造商全稱:TDK Electronics 功能描述:CCITT V.23, V.22, V.21 Single-Chip Modem |
| 73K322L-IP | 制造商:TDK 制造商全稱:TDK Electronics 功能描述:CCITT V.23, V.22, V.21 Single-Chip Modem |
| 73K324BL | 制造商:TERIDIAN 制造商全稱:TERIDIAN 功能描述:Single-Chip Modem w/ Integrated Hybrid |
| 73K324BL-IGT | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Single-Chip Modem w/Integrated Hybrid |
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