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參數(shù)資料
| 型號： | MT8972 |
| 廠商： | Mitel Networks Corporation |
| 英文描述： | () |
| 中文描述： | （） |
| 文件頁數(shù)： | 2/5頁 |
| 文件大?。?/td> | 27K |
| 代理商： | MT8972 |
MSAS-42
Application Sheet
A-2
Convergence Times
Characteristics
Sym
Min
Typ
Max
Units
Test Conditions
1
Attack Off at 80 kbit/s
T
c80
T
c160
T
ac80
T
ac160
8.5
17.50
s
2
Attack Off at 160 kbit/s
4.0
8.80
s
3
Attack On at 80 kbit/s
0.8
1.75
s
Atk. for 60ms.
4
Attack On at 160 kbit/s
0.4
.85
s
Atk. for 30ms.
9. Why is a 10.24 MHz crystal used as opposed
to some other frequency
The 10.24 MHz is used because it is the lowest
common multiple of the data rate clocks (80 and 160
kbit/s) and the ST-BUS clocks (2.048 and 4.096 Mbit/
s).
10. Can the DNIC operate with a 1.544 Mhz. data
stream
No. The internal operation of the DNIC is set up to
work with a 2.048 MHz data stream such as the ST-
BUS data stream. Operation with a 1.544 MHz
network would only be possible if an interface was
available to reformat the 1.544 MHz data into 2.048
MHz format, and a 10.24 MHz clock source was
provided.
11. What types of packages does the DNIC come
in
The DNIC is available in 22 Pin CERDIP and PDIP
and also in 28 Pin Plastic Leaded Chip Carrier
(PLCC).
12. Is the DNIC an analog or digital device
The DNIC is both an analog and digital device. It
provides the interface between a digital system (ST-
BUS) and an analog system (2 wire telephone loop
plant), thus it has components internally which
provide the necessary interface capabilities.
13. What does the PLL operate on
A phase-locked loop is essentially a frequency
comparator with feedback. In the DNIC, the PLL uses
the incoming data stream as one input frequency,
and a generated 160 kHz or 80 kHz as the other. The
output clock from the PLL is a 10.24 MHz. phase-
locked clock. This clock is divided down to get RCK
which is then compared with the incoming data
stream. The 10.24 MHz output clock is then adjusted
accordingly.
14. How can you determine whether the DNIC or
system is not operating properly
The DNIC has special loopback testing capabilities
which allows it to diagnose itself either via end-to-
end testing, or via internal testing. This mode is
accessed by using the received C-channel and the
diagnostics register.
15. What are the leading causes of echoes in a
digital network
The leading causes of echoes are bridged taps,
cable gauge changes, and impedance mismatches.
16. What effect do bridged taps have on system
performance
The effect of the bridged taps depends largely on
where in the network these bridge taps are located.
If they are at the transmitter / receiver, then the effect
is quite severe. The length of the bridged taps is also
of concern. The most severe bridged tap is of the
quarter wave length (around 250 meters). Other
factors are whether the bridged tap is terminated or
not, and what impedance is at the termination.
Signal degradation up to 6dB per tap may be
encountered.
17. Are the ST-BUS transmit and receive frames
aligned with respect to each other, or are they
skewed
The ST-BUS transmit and receive frames are aligned
with respect to each other. This is achieved by
double buffering the transmit data, and triple
buffering the receive data
.
This allows transmission
and reception to be activated by the same pulse.
18. What happens with the unused ST-BUS
channels
Once the DNIC has finished its active channels (4 at
160 kbit/s), then the F0o pin is set. The rest of the
ST-BUS channels are set to high impedance. This
allows for other DNICs to access the unused
channels on the ST-BUS. By using the F0o pin
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MT8976 | Ultraframer DS3/E3/DS2/E2/DS1/E1/DS0 |
| MT8976 | Ultraframer DS3/E3/DS2/E2/DS1/E1/DS0 |
| MT8976AC | Ultraframer DS3/E3/DS2/E2/DS1/E1/DS0 |
| MT8976AE | Ultraframer DS3/E3/DS2/E2/DS1/E1/DS0 |
| MT8976AP | Ultraframer DS3/E3/DS2/E2/DS1/E1/DS0 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| 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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