 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
MT8889C Datasheet(PDF) 5 Page - Mitel Networks Corporation |
|
||||||||||||||||||||||||||||||
MT8889C Datasheet(HTML) 5 Page - Mitel Networks Corporation |
|
|
5 / 18 page  MT8889C/MT8889C-1 4-111 applications, leaving R1 to be selected by the designer. Different steering arrangements may be used to select independent tone present (tGTP) and tone absent (tGTA) 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 tREC 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 tREC with a long tDO 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 MT8889C/ MT8889C-1, 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 ‘accept’ 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 Vin ESt St/GT RX0-RX3 b3 b2 Read Status Register IRQ/CP EVENTS AB C D E F tREC tREC tID tDO TONE #n TONE #n + 1 TONE #n + 1 tDP tDA tGTP tGTA tPStRX tPStb3 DECODED TONE # (n-1) # n # (n + 1) VTSt |
Similar Part No. - MT8889C |
|
Similar Description - MT8889C |
|
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.COM |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
