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參數(shù)資料
| 型號(hào)： | MT8843 |
| 廠商： | Mitel Networks Corporation |
| 英文描述： | Calling Number Identification Circuit(主叫識(shí)別電路（提供各種主叫線信息傳遞設(shè)備的接口）) |
| 中文描述： | 主叫號(hào)碼識(shí)別電路（主叫識(shí)別電路（提供各種主叫線信息傳遞設(shè)備的接口）） |
| 文件頁數(shù)： | 5/26頁 |
| 文件大?。?/td> | 178K |
| 代理商： | MT8843 |
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MT8843
5-35
power-down mode to conserve power in a battery
operated TE.
2. Ring Burst Detection
CCA does not support the dual tone alert signal
(refer to Dual Tone Alert Signal Detection section).
Instead, CCA requires that the TE be able to detect a
single burst of ringing (duration 200-450ms) that
precedes CLIP FSK data. The ring burst may vary
from 30 to 75Vrms and is approximately 25Hz.
Again in a TE designed for CCA CLIP, the TRIGout
high to low transition may be used to interrupt or
wake-up the microcontroller. The controller can thus
be put into power-down mode to conserve power in a
battery operated TE.
3. Ring Detection
In Bellcore’s CND/CNAM scheme, the CID FSK data
is transmitted between the first and second ringing
cycles. The circuit in Figure 3 will generate a ring
envelope signal (active low) at TRIGout for a ring
voltage of at least 40Vrms. R5 and C3 filter the ring
signal to provide an envelope output.
The diode bridge shown in Figure 3 works for both
single ended and balanced ringing. A fraction of the
ring voltage is applied to the TRIGin input. When the
voltage at TRIGin is above the Schmitt trigger high
going threshold V
T+
, TRIGRC is pulled low as C3
discharges. TRIGout stays low as long as the C3
voltage stays below the minimum V
T+
.
In a CPE designed for CND/CNAM, the TRIGout
high to low transition may be used to interrupt or
wake-up the microcontroller. The controller can thus
be put into power-down mode to conserve power.
If precise ring duration determination is critical,
capacitor C3 in Figure 3 may be removed. The
microcontroller will now be able to time the ring
duration directly. The result will be that TRIGout will
be low only as long as the ringing signal is present.
Previously the RC time constant would cause only
one interrupt.
Dual Tone Alert Signal Detection
According to BT specification SIN227 the Idle State
Tone Alert Signal allows more reliable detection of
Caller Display Service signals. The Idle State Tone
Alert Signal follows the line reversal and a silence
period. The characteristics of the BT idle state
alerting tone is shown in Table 1.
Bellcore specifies a similar dual tone alert signal
called CPE Alerting Signal (CAS) for use in off-hook
data transmission. Bellcore states that the CPE
should be able to detect the CPE Alerting Signal in
the presence of near end speech.
The dual tone alert signal is separated into a high
and a low tone by two bandpass filters. A detection
algorithm examines the two filter outputs to
determine the presence of a dual tone alert signal.
The ESt pin goes high when both tones are present.
Note that ESt is only a preliminary indication . The
indication must be sustained over the tone present
guard time to be considered valid. Tone present and
tone absent guard times can be implemented with
external RC components. The tone present guard
time rejects signals of insufficient duration. The tone
absent guard time masks momentary detection
dropout once the present guard time has been
satisfied. StD is the guard time qualified detector
output.
a. In the future BT may specify the off-hook signal level as
-15dBm to -34dBm per tone for BT CIDCW.
b. The signal power is expressed in dBm referenced to 600 ohm
at the CPE A/B (tip/ring) interface.
c. ASL = active speech level expressed in dBm referenced to
600 ohm at the CPE tip/ring interface. The level is measured
according to method B of Recommendation P.56 "Objective
Measurement of Active Speech Level" published in the CCITT
Blue Book, volume V "Telephone Transmission Quality" 1989.
EPL (Equivalent Peak Level) = ASL+11.7dB
d. SIN227 suggests that the recognition time should be not less
than 20ms if both tones are detected.
Item
BT
Bellcore
Low tone
frequency
2130Hz ±
±
±1.1%
2130Hz±
±
0.5%
High tone
frequency
2750Hz±
±
1.1%
2750Hz±
±
0.5%
Received
signal level
-2dBV to -40dBV
per tone on-hook
a
(0.22dBm
b
to
-37.78dBm)
-14dBm
b
to
- 32dBm per tone
off-hook
Signal reject
level
-46dBV
(-43.78dBm)
-45dBm
Signal level
differential
(twist)
up to 7dB
up to 6dB
Unwanted
signals
<= -20dB
(300-3400Hz)
88ms to 110ms
d
<= -7dBm ASL
c
near end speech
Duration
75ms to 85ms
Speech
present
No
Yes
Table 1 - Dual Tone Alert Signal
Characteristics
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MT8888C | Integrated DTMF Transceiver with Intel Micro Interface(雙音多頻信號(hào)（DTMF）收發(fā)器（帶Intel微接口）) |
| 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 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MT8843AE | 制造商:Mitel Networks Corporation 功能描述:TELEPHONE CALLING NO IDENT CKT, PDIP24 |
| MT8843AS | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:CMOS Calling Number Identification Circuit 2 Preliminary Information |
| MT8860 | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:DTMF DECODER |
| MT8860XC | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:DTMF DECODER |
| MT8860XE | 制造商:Hitachi 功能描述:DTMF RECEIVER, 18 Pin, Plastic, DIP 制造商:Microsemi Corporation 功能描述:DTMF RECEIVER, 18 Pin, Plastic, DIP 制造商:Mitel Networks Corporation 功能描述:DTMF RECEIVER, 18 Pin, Plastic, DIP |
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