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參數(shù)資料
| 型號(hào)： | MT8972 |
| 廠商： | Mitel Networks Corporation |
| 英文描述： | () |
| 中文描述： | （） |
| 文件頁(yè)數(shù)： | 4/5頁(yè) |
| 文件大?。?/td> | 27K |
| 代理商： | MT8972 |
MSAS-42
Application Sheet
A-4
from the composite signal made up of the far-end
signal and actual reflected echo. An error signal,
either positive or negative (i.e., sign bit), is generated
which serves to either increment or decrement the
value of the echo estimate stored in RAM. The next
time the same data sequence is transmitted, the new
value of echo estimate is used, and the process
repeats itself. The RAM is active continuously and
adapts to any changes in the line, characteristics,
hence it is referred to as an adaptive echo canceler.
28. What is the recommended value to use as a
termination impedance
The termination impedance (Z
t
) designated by R2 C2
and C2’ in Figure 18 and 19 of the datasheet, is used
to match the characteristic impedance of the
telephone line (Z
o
). Z
t
should be approximately equal
to four times Z
o
. This is due to the four times
impedance
multiplication
transformer. C2‘ has been placed in parallel to R2 to
correct the phase of the signal being returned to L
in
.
Tailoring of R2, C2, and C2‘ can be done for specific
situations such as bit rate, cable gauge, and cable
characteristics. Recommended values for 160 kbit/s
are: R2= 390 ohms, C2=22 nF, C2‘=1.5 nF. For 80
kbit/s R2=390 ohms, C2=22 nF, C2‘=3.3 nF.
through
the
2:1
29. How does the DNIC transmit information in
the Modem Mode
The DNIC can be used as a high speed, limited
distance, modem. It is capable of transmitting up to
160 kHz of NRZ data either synchronously or
asynchronously. The DNIC samples the signal
presented to its Di pin at the selected baud rate. This
signal is converted to a biphase signal and sent onto
the line. At the far end, the DNIC decodes the
biphase signal, and recreates the equivalent NRZ
data pattern.
30. What loopback functions does the DNIC
provide
The DNIC has three loopback options which are
activated via the C-channel and the diagnostics
register. The first loopback loops DSTi to DSTo at the
local end for system diagnostics. The second
loopback loops back L
out
to L
in
at the local end for
system and DNIC diagnostics. The third loopback
loops back DSTo to DSTi at the remote end to
provide full end to end diagnostics. In the DSTi to
DSTo and DSTo to DSTi cases, it’s only the B
channels which are looped back. With the L
out
to L
in
loopback, the entire Biphase output stream is looped
back.
31. What are the major applications of the DNIC
The DNIC is essentially a digital transmission device.
It can easily be used in voice and data transmission
systems. The DNIC is an excellent PBX device,
allowing flexible digital line card and terminal design
using 2 wire transmission. ISDN type services can be
carried by the DNIC over the U-Interface. The DNIC
can provide a high speed data stream for multiplexed
lower rate data, such as RS-232C. The DNIC can
also be used as a SLC-96, or D4 channel bank
interface, allowing easy multiplexing into a T1 stream.
32. What further information is available on the
DNIC
The DNIC is supported by a team of highly skilled
applications
engineers
information to potential users in order to facilitate the
design-in of the DNIC. There is a DNIC Application
Note (MSAN-124) available which highlights some of
the many potential applications of the DNIC. Reprints
of several DNIC related published papers are also
available.
providing
practical
33. Loop Extender Application.
An application circuit is available which can be used
to increase the performance of the DNIC. MSAS-46
describes the extender circuit configuration as well
as specifying values for 80 and 160 kbit/s operation.
With the extender circuit, performance in the range
of 42 dB of cable attenuation can be achieved. This
corresponds to over 6 km on standard 24 AWG
telephone cable for 80 kbit/s and 5 km for 160 kbit/s.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
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| MT8972B | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:ISO2-CMOS ST-BUS⑩ FAMILY Digital Subscriber Interface Circuit Digital Network Interface Circuit |
| MT8972BC | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:ISO2-CMOS ST-BUS⑩ FAMILY Digital Subscriber Interface Circuit Digital Network Interface Circuit |
| MT8972BE | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:ISO2-CMOS ST-BUS⑩ FAMILY Digital Subscriber Interface Circuit Digital Network Interface Circuit |
| MT8972BP | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:ISO2-CMOS ST-BUS⑩ FAMILY Digital Subscriber Interface Circuit Digital Network Interface Circuit |
| MT8976 | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:ISO-CMOS ST-BUS⑩ FAMILY T1/ESF Framer Circuit |
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