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參數(shù)資料
| 型號： | MH89726 |
| 廠商： | Mitel Networks Corporation |
| 英文描述： | MT8972 Loop Extender Circuits Advance Information |
| 中文描述： | MT8972循環(huán)擴(kuò)展電路進(jìn)展信息 |
| 文件頁數(shù)： | 3/6頁 |
| 文件大?。?/td> | 119K |
| 代理商： | MH89726 |
9-129
Advance Information
MH89726/728
Functional Description
The MH89726/728 are 10 pin SIL thick film hybrid
circuits that may be used to extend the loop range
capability of the MT8972 (DNIC). For a detailed
description of the DNIC, refer to the MT8972 data
sheet.
Figure 1 shows a block diagram of the Loop
Extender Circuit (LEC). The LEC takes the line
signal which is transmitted by the DNIC on L
OUT
, pre-
equalizes, and amplifies it before sending it to the
termination network. The gain of the TX amplifier is
adjustable by using an external resistor between
pins 1 and 2. If no external resistor is added, TX
GAIN
and TX
OUT
must be shorted together, and the default
gain condition exists. This gain results in a transmit
signal power level of +10 dBm.
On the receive side, the LEC receives the differential
line signal from the transformer, and performs first-
order pre-cancellation as well as gain and phase
adjustment of the receive signal. The signal is then
output on RX
OUT
which is connected to L
IN
of the
MT8972.
Tables 1 and 2 show typical results obtained by
using the LEC with the MT8972. Actual distance
achieved may vary depending on the characteristics
of the transmission cable being used. Most
important factors include cable attenuation (dB/km),
bridged taps, and crosstalk interference.
The LEC is powered typically from ±15 Volts if dual
power supplies are available. Alternately 0 to +30
Volts, or -30 to 0 Volts can be used if only a single
power supply is available.
Applications
Figure 3 shows a typical connection diagram of the
MT8972 and MH89726/728. RX
OUT
and T
XIN
of the
LEC are connected to L
OUT
and L
IN
of the DNIC
respectively. Pins 5, 6 and 7 are the power supply
pins, with the voltages being supplied as indicated in
the table . An external resistor, R
EXT
, may be used
to increase the gain of the transmitter. Without R
EXT
,
TX
GAIN
and TX
OUT
are shorted together resulting in
a transmit power level of +10 dBm.
R
LL
, R
L
, and C
L
comprise the termination network
and are used to match the characteristic impedance
of the transmission line. This provides the 4 wire to 2
wire hybrid conversion necessary for twisted pair
transmission.
Figure 4 shows a typical application of the LEC. On
short loops, jumpers (or switches) could be used to
remove the LEC from the circuit. For longer loops,
the jumpers could be changed to include the LEC in
the signal path.
Figure 3 - Typical Connection Diagram for MT8972 and MH89726/728
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
MT8972
(DNIC)
MH89726
or
MH89728
+ 5V
22
1
21
11
D1
D2
10
9
8
7
6
5
4
3
2
1
To Power Supplies
R
ext
R
LL
R
L
C
L
0.33
μ
F
1.0
μ
F
100k
D1, D2 IN5817
R
ext
Set for different gain requirements
MH89726
160 kbit/s
MH89728
80 kbit/s
R
LL
R
L
C
L
3.9k
, 5%
430
, 2%
15nF, 5%
3k
, 5%
430
, 2%
12nF, 5%
Power
Supply
DUAL
SINGLE
SINGLE
*Use 0.33
μ
F capacitor to GND
Pin 7
(V +)
+ 15V
GND
+ 30V
Pin 6
(V
Bias
)
GND
GND*
GND*
Pin 5
(V-)
- 15V
- 30V
GND
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MH89728 | MT8972 Loop Extender Circuits Advance Information |
| MH89760B | Ultraframer DS3/E3/DS2/E2/DS1/E1/DS0 |
| MH89760BN | Ultraframer DS3/E3/DS2/E2/DS1/E1/DS0 |
| MH89760BS | Ultraframer DS3/E3/DS2/E2/DS1/E1/DS0 |
| MH89761 | T1 Transmit Equalizer Advance Information |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MH89728 | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:MT8972 Loop Extender Circuits Advance Information |
| MH89760 | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| MH89760B | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:ST-BUS⑩ FAMILY T1/ESF Framer & Interface Preliminary Information |
| MH89760BN | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:ST-BUS⑩ FAMILY T1/ESF Framer & Interface Preliminary Information |
| MH89760BS | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:ST-BUS⑩ FAMILY T1/ESF Framer & Interface Preliminary Information |
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