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參數(shù)資料
| 型號： | MT8888C |
| 廠商： | Mitel Networks Corporation |
| 英文描述： | Integrated DTMF Transceiver with Intel Micro Interface(雙音多頻信號（DTMF）收發(fā)器（帶Intel微接口）) |
| 中文描述： | 集成雙音多頻收發(fā)器與英特爾微型接口（雙音多頻信號（DTMF）的收發(fā)器（帶英特爾微接口）） |
| 文件頁數(shù)： | 5/21頁 |
| 文件大?。?/td> | 171K |
| 代理商： | MT8888C |
MT8888C
4-93
applications, leaving R1 to be selected by the
designer. Different steering arrangements may be
used to select independent tone present (t
GTP
) and
tone absent (t
GTA
) guard times. This may be
necessary to meet system specifications which place
both accept and reject limits on tone duration and
interdigital pause. Guard time adjustment also allows
the designer to tailor system parameters such as talk
off and noise immunity.
Increasing t
REC
improves talk-off performance since
it reduces the probability that tones simulated by
speech will maintain a valid signal condition long
enough to be registered. Alternatively, a relatively
short t
REC
with a long t
DO
would be appropriate for
extremely noisy environments where fast acquisition
time and immunity to tone drop-outs are required.
Design information for guard time adjustment is
shown in Figure 6. The receiver timing is shown in
Figure 7 with a description of the events in Figure 9.
Call Progress Filter
A call progress mode, using the MT8888C, can be
selected allowing the detection of various tones,
which identify the progress of a telephone call on the
network. The call progress tone input and DTMF
input are common, however, call progress tones can
only be detected when CP mode has been selected.
DTMF signals cannot be detected if CP mode has
been selected (see Table 7). Figure 8 indicates the
useful detect bandwidth of the call progress filter.
Frequencies presented to the input, which are within
the ‘a(chǎn)ccept’ bandwidth limits of the filter, are hard-
limited by a high gain comparator with the IRQ/CP
pin serving as the output. The squarewave output
obtained from the schmitt trigger can be analyzed by
a microprocessor or counter arrangement to
determine the nature of the call progress tone being
detected. Frequencies which are in the ‘reject’ area
will not be detected and consequently the IRQ/CP
pin will remain low.
Figure 8 - Call Progress Response
LEVEL
(dBm)
FREQUENCY (Hz)
-25
0
250
500
750
= Reject
= May Accept
= Accept
Figure 7 - Receiver Timing Diagram
V
in
ESt
St/GT
RX
0
-RX
3
b3
b2
Read
Status
Register
IRQ/CP
EVENTS
A
B
C
D
E
F
t
REC
t
REC
t
ID
t
DO
TONE #n
TONE
#n + 1
TONE
#n + 1
t
DP
t
DA
t
GTP
t
GTA
t
PStRX
t
PStb3
DECODED TONE # (n-1)
# n
# (n + 1)
V
TSt
相關PDF資料 |
PDF描述 |
|---|---|
| MT8889CC-1 | Integrated DTMFTransceiver with Adaptive Micro Interface |
| MT8889CN-1 | Integrated DTMFTransceiver with Adaptive Micro Interface |
| MT8889CS-1 | Integrated DTMFTransceiver with Adaptive Micro Interface |
| MT8889C | Integrated DTMFTransceiver with Adaptive Micro Interface |
| MT8889CC | Integrated DTMFTransceiver with Adaptive Micro Interface |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| MT8888CC | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:Integrated DTMFTransceiver with Intel Micro Interface |
| MT8888CC-1 | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:Integrated DTMFTransceiver with Intel Micro Interface |
| MT8888CE | 制造商:Microsemi Corporation 功能描述: |
| MT8888CE1 | 制造商:Microsemi Corporation 功能描述:DTMF TXRX 3.58MHZ CMOS 5V 20PDIP - Rail/Tube 制造商:Microsemi Corporation 功能描述:PB FREE DTMF TRANSCEIVER 制造商:MICROSEMI CONSUMER MEDICAL PRODUCT GROUP 功能描述:IC TXRX DTMF 20PDIP 制造商:Microsemi Corporation 功能描述:IC TXRX DTMF 20PDIP |
| MT8888CE-1 | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:Integrated DTMFTransceiver with Intel Micro Interface |
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