ml7020mb Oki Semiconductor, ml7020mb Datasheet - Page 10

• Manufacturer Part Number: ml7020mb
• Description: 1200 Bps Modem For Remote Control Systems
• Manufacturer: Oki Semiconductor

t
t
t
t
t
t
t
t
t
1 Semiconductor
s
I
p
ba
bb
c
g
d
sp
:
:
:
:
:
:
DTMF receive data
: Instantaneous break protection period 1
:
: Instantaneous break protection period 2
DTMF signal
Input signal persistence duration (detection)
Normal reception is made when the input signal persistence duration is equal to t
Input signal persistence duration (non-detection)
The input signal is ignored when the input signal persistence duration is less than t
receive data are not output.
Signal quiet duration
The DTMF receive data and SP are reset if the input continues to be in the no-signal condition for a
duration equal to t
Also, even if the receive data changes during DTMF signal reception, SP continues to be “1” and the
DTMF receive data may remain in the initial value and may not change, if the signal quiet duration is less
than t
This is applicable to the period after the input signal has arrived and until the timing when SP becomes “1”.
In other words, SP and DTMF receive data are output normally even if a no-signal condition of a duration
less than t
This is applicable when SP is “1” (during output of the receive data). In other words, SP and the DTMF
receive data are not reset even if a no-signal condition of a duration less than t
reception.
For ensuring normal reception, make sure that the signal repetition period is equal to t
Detection delay time
The DTMF receive data is output with a delay of t
Detection hold time
The output of SP or the DTMF receive data is stopped with a delay of t
signal.
SP delay time
SP is output after a delay of t
DTMF receive data when the rising edge of SP is detected.
SP
p
(including when it changes without any instantaneous break).
ba
occurs.
t
p
l
or longer.
Figure 3 DTMF reception timing
sp
t
g
relative to the output of the DTMF receive data. Therefore, latch the
t
s
t
sp
t
c
g
relative to the appearance of the input signal.
t
d
t
p
t
ba
d
after the termination of the input
t
bb
s
or more.
I
, and the SP and DTMF
bb
c
occurs during signal
or more.
FEDL7020-02
ML7020
10/19