Os motores de busca de Datasheet de Componentes eletrônicos
  Portuguese  ▼
ALLDATASHEETPT.COM

X  

M-8888 Folha de dados(PDF) 3 Page - Clare, Inc.

Nome de Peças M-8888
Descrição Electrónicos  DTMF Transceiver
Download  14 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Fabricante Electrônico  CLARE [Clare, Inc.]
Página de início  http://www.clare.com
Logo CLARE - Clare, Inc.

M-8888 Folha de dados(HTML) 3 Page - Clare, Inc.

  M-8888 Datasheet HTML 1Page - Clare, Inc. M-8888 Datasheet HTML 2Page - Clare, Inc. M-8888 Datasheet HTML 3Page - Clare, Inc. M-8888 Datasheet HTML 4Page - Clare, Inc. M-8888 Datasheet HTML 5Page - Clare, Inc. M-8888 Datasheet HTML 6Page - Clare, Inc. M-8888 Datasheet HTML 7Page - Clare, Inc. M-8888 Datasheet HTML 8Page - Clare, Inc. M-8888 Datasheet HTML 9Page - Clare, Inc. Next Button
Zoom Inzoom in Zoom Outzoom out
 3 / 14 page
background image
M-8888
www.clare.com
3
Rev. 1
switched capacitor bandpass filters with bandwidths
that correspond to the low and high group frequencies
listed in the Tone Encoding/Decoding below. The low
group filter incorporates notches at 350 and 440 Hz,
providing excellent dial tone rejection. Each filter out-
put is followed by a single-order switched capacitor fil-
ter that smoothes the signals prior to limiting. Limiting
is performed by high-gain comparators with hysteresis
to prevent detection of unwanted low-level signals.
The comparator outputs provide full-rail logic swings
at the incoming DTMF signal frequencies.
A decoder employs digital counting techniques to
determine the frequencies of the incoming tones, and
to verify that they correspond to standard DTMF fre-
quencies. A complex averaging algorithm protects
against tone simulation by extraneous signals (such
as voice), while tolerating small deviations in frequen-
cy. The algorithm provides an optimum combination of
immunity to talkoff with tolerance to interfering fre-
quencies (third tones) and noise. When the detector
recognizes the presence of two valid tones (referred to
as signal condition), the early steering (ESt) output
goes to an active state. Any subsequent loss of signal
condition will cause ESt to assume an inactive state.
Steering Circuit:
Before a decoded tone pair is registered, the receiver
checks for a valid signal duration (referred to as “char-
acter recognition condition”). This check is performed
by an external RC time constant driven by ESt. A logic
high on ESt causes V
C (see the Basic Steering Circuit
above) to rise as the capacitor discharges. Provided
that the signal condition is maintained (ESt remains
high) for the validation period (t
GTP), VC reaches the
threshold (V
TSt) of the steering logic to register the
tone pair, latching its corresponding 4-bit code (see
the Tone Encoding/Decoding on left) into the receive
data register.
At this point the StGT output is activated and drives V
C
to V
DD. StGT continues to drive high as long as ESt
remains high. Finally, after a short delay to allow the
output latch to settle, the delayed steering output flag
goes high, signaling that a received tone pair has
been registered. It is possible to monitor the status of
the delayed steering flag by checking the appropriate
bit in the status register. If interrupt mode has been
selected, the IRQ/CP pin will pull low when the
delayed steering flag is active.
The contents of the output latch are updated on an
active delayed steering transition. This data is pre-
sented to the 4-bit bidirectional data bus when the
receive data register is read. The steering circuit works
in reverse to validate the interdigit pause between sig-
nals. Thus, as well as rejecting signals too short to be
considered valid, the receiver will tolerate signal inter-
ruptions (dropout) too short to be considered a valid
pause. This capability, together with the ability to
select the steering time constants externally, allows
the designer to tailor performance to meet a wide vari-
ety of system requirements.
Guard Time Adjustment: The simple steering circuit
shown in the Basic Steering Circuit above is adequate
for most applications. Component values are chosen
according to the formula:
t
REC = tDP + tGTP
T
ID = tDA + tGTA
Tone Encoding/Decoding
F
LOW
F
HIGH
Digit
D3
D2
D1
D0
697
1209
1
0
0
0
1
697
1336
2
0
0
1
0
697
1477
3
0
0
1
1
770
1209
4
0
1
0
0
770
1336
5
0
1
0
1
770
1477
6
0
1
1
0
852
1209
7
0
1
1
1
852
1336
8
1
0
0
0
852
1477
9
1
0
0
1
941
1336
0
1
0
1
0
941
1209
*
1
0
1
1
941
1477
#
1
1
0
0
697
1633
A
1
1
0
1
770
1633
B
1
1
1
0
852
1633
C
1
1
1
1
941
1633
D
0
0
0
0
0 = logic low, 1 = logic high
Basic Steering Circuit


Nº de peça semelhante - M-8888

Fabricante ElectrônicoNome de PeçasFolha de dadosDescrição Electrónicos
logo
Clare, Inc.
M-8888 CLARE-M-8888 Datasheet
457Kb / 14P
   DTMF Transceiver
M-8888-01P CLARE-M-8888-01P Datasheet
457Kb / 14P
   DTMF Transceiver
M-8888-01SM CLARE-M-8888-01SM Datasheet
457Kb / 14P
   DTMF Transceiver
M-8888-01T CLARE-M-8888-01T Datasheet
457Kb / 14P
   DTMF Transceiver
More results

Descrição semelhante - M-8888

Fabricante ElectrônicoNome de PeçasFolha de dadosDescrição Electrónicos
logo
OKI electronic componet...
MSM7524 OKI-MSM7524 Datasheet
128Kb / 21P
   DTMF Transceiver
ML7005 OKI-ML7005 Datasheet
202Kb / 25P
   DTMF Transceiver
logo
Clare, Inc.
M8880 CLARE-M8880 Datasheet
562Kb / 13P
   DTMF Transceiver
logo
LAPIS Semiconductor Co....
ML7005 LAPIS-ML7005 Datasheet
474Kb / 26P
   DTMF Transceiver
logo
Clare, Inc.
M8888-R1 CLARE-M8888-R1 Datasheet
457Kb / 14P
   DTMF Transceiver
logo
List of Unclassifed Man...
ML7005 ETC2-ML7005 Datasheet
474Kb / 26P
   DTMF Transceiver
logo
California Micro Device...
CM8880 CALMIRCO-CM8880 Datasheet
745Kb / 16P
   CMOS Integrated DTMF Transceiver
logo
Clare, Inc.
M-8880 CLARE-M-8880 Datasheet
841Kb / 13P
   M-8880 DTMF Transceiver
logo
Zarlink Semiconductor I...
MT8889C ZARLINK-MT8889C Datasheet
494Kb / 31P
   Integrated DTMF Transceiver with Adaptive Micro Interface
MT8888C ZARLINK-MT8888C Datasheet
684Kb / 25P
   Integrated DTMF Transceiver with Intel Micro Interface
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14


Folha de dados Download

Go To PDF Page


Ligação URL




Privacy Policy
ALLDATASHEETPT.COM
ALLDATASHEET é útil para você?  [ DONATE ] 

Sobre Alldatasheet   |   Publicidade   |   Contato conosco   |   Privacy Policy   |   roca de Link   |   Lista de Fabricantes
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
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