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MT8880CS-1 参数 Datasheet PDF下载

MT8880CS-1图片预览
型号: MT8880CS-1
PDF下载: 下载PDF文件 查看货源
内容描述: ISO2 -CMOS集成DTMFTransceiver [ISO2-CMOS Integrated DTMFTransceiver]
分类和应用:
文件页数/大小: 18 页 / 315 K
品牌: MITEL [ MITEL NETWORKS CORPORATION ]
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ISO2-CMOS MT8880C/MT8880C-1  
and the transmitter gated on and off by an external  
hardware or software timer.  
Burst Mode  
In certain telephony applications it is required that  
DTMF signals being generated are of a specific  
duration determined either by the particular  
application or by any one of the exchange transmitter  
specifications currently existing. Standard DTMF  
signal timing can be accomplished by making use of  
the Burst Mode. The transmitter is capable of issuing  
symmetric bursts/pauses of predetermined duration.  
This burst/pause duration is 51 ms±1 ms which is a  
standard interval for autodialer and central office  
applications. After the burst/pause has been issued,  
the appropriate bit is set in the Status Register  
indicating that the transmitter is ready for more data.  
The timing described above is available when DTMF  
mode has been selected. However, when CP mode  
(Call Progress mode) is selected, a second burst/  
Single Tone Generation  
A single tone mode is available whereby individual  
tones from the low group or high group can be  
generated. This mode can be used for DTMF test  
equipment applications, acknowledgment tone  
generation and distortion measurements. Refer to  
Control Register B description for details.  
Distortion Calculations  
The MT8880C/C-1 is capable of producing precise  
tone bursts with minimal error in frequency (see  
Table 1). The internal summing amplifier is followed  
by a first-order lowpass switched capacitor filter to  
minimize harmonic components and intermodulation  
products. The total harmonic distortion for a single  
tone can be calculated using Equation 1, which is the  
ratio of the total power of all the extraneous  
frequencies to the power of the fundamental  
frequency expressed as a percentage. The Fourier  
pause  
time of 102 ms ±2 ms is available. This  
extended interval is useful when precise tone bursts  
of longer than 51 ms duration and 51 ms pause are  
desired. Note that when CP mode and Burst mode  
have been selected, DTMF tones may be transmitted  
only and not received.  
components of the tone output correspond to V ....  
In applications where a non-standard burst/pause  
duration is required, burst mode must be disabled  
2f  
V
as measured on the output waveform. The total  
nf  
harmonic distortion for a dual tone can be calculated  
EXPLANATION OF EVENTS  
A)  
B)  
C)  
TONE BURSTS DETECTED, TONE DURATION INVALID, RX DATA REGISTER NOT UPDATED.  
TONE #n DETECTED, TONE DURATION VALID, TONE DECODED AND LATCHED IN RX DATA REGISTER.  
END OF TONE #n DETECTED, TONE ABSENT DURATION VALID, INFORMATION IN RX DATA REGISTER  
RETAINED UNTIL NEXT VALID TONE PAIR.  
D)  
E)  
F)  
TONE #n+1 DETECTED, TONE DURATION VALID, TONE DECODED AND LATCHED IN RX DATA REGISTER.  
ACCEPTABLE DROPOUT OF TONE #n+1, TONE ABSENT DURATION INVALID, DATA REMAINS UNCHANGED.  
END OF TONE #n+1 DETECTED, TONE ABSENT DURATION VALID, INFORMATION IN RX DATA REGISTER  
RETAINED UNTIL NEXT VALID TONE PAIR.  
EXPLANATION OF SYMBOLS  
Vin  
DTMF COMPOSITE INPUT SIGNAL.  
ESt  
EARLY STEERING OUTPUT. INDICATES DETECTION OF VALID TONE FREQUENCIES.  
STEERING INPUT/GUARD TIME OUTPUT. DRIVES EXTERNAL RC TIMING CIRCUIT.  
St/GT  
RX0-RX3 4-BIT DECODED DATA IN RECEIVE DATA REGISTER  
b3  
DELAYED STEERING. INDICATES THAT VALID FREQUENCIES HAVE BEEN PRESENT/ABSENT FOR THE  
REQUIRED GUARD TIME THUS CONSTITUTING A VALID SIGNAL. ACTIVE LOW FOR THE DURATION OF A  
VALID DTMF SIGNAL.  
b2  
INDICATES THAT VALID DATA IS IN THE RECEIVE DATA REGISTER. THE BIT IS CLEARED AFTER THE STATUS  
REGISTER IS READ.  
IRQ/CP INTERRUPT IS ACTIVE INDICATING THAT NEW DATA IS IN THE RX DATA REGISTER. THE INTERRUPT IS  
CLEARED AFTER THE STATUS REGISTER IS READ.  
tREC  
tREC  
tID  
MAXIMUM DTMF SIGNAL DURATION NOT DETECTED AS VALID.  
MINIMUM DTMF SIGNAL DURATION REQUIRED FOR VALID RECOGNITION.  
MINIMUM TIME BETWEEN VALID SEQUENTIAL DTMF SIGNALS.  
MAXIMUM ALLOWABLE DROPOUT DURING VALID DTMF SIGNAL.  
TIME TO DETECT VALID FREQUENCIES PRESENT.  
TIME TO DETECT VALID FREQUENCIES ABSENT.  
GUARD TIME, TONE PRESENT.  
tDO  
tDP  
tDA  
tGTP  
tGTA  
GUARD TIME, TONE ABSENT.  
Figure 11 - Description of Timing Events  
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