MT3171B Datasheet, PDF (11/15 Pages) Zarlink Semiconductor Inc – Wide Dynamic Range DTMF Receiver

MT3170B/71B, MT3270B/71B, MT3370B/71B
INPUT
DTMF
Tone #n
t_DP
ESt
(MT3x70B)
t_REC
DStD
(MT3x71B)
t_REC
t_DA
t_ID
t_DO
DTMF
Tone #n + 1
DTMF
Tone
#n + 1
Data Sheet
Input
Signal
ACK
LSB MSB
SD
LSB MSB
b₀b₁b₂b₃
b₀b₁b₂b₃
t_{DO - maximum allowable dropout during valid DTMF signals. (MT3x7xB).}
t_{ID - minimum time between valid DTMF signals (MT3x71B).}
t_{REC - maximum DTMF signal duration not detected as valid (MT3x7xB).}
t_{REC - minimum DTMF signal duration required for valid recognition (MT3x71B).}
t_{DA - time to detect the absence of valid DTMF signals (MT3x70B).}
t_{DP - time to detect the presence of valid DTMF signals (MT3x70B).}
t_{SA - supervisory tone integrator attack time (MT3x7xB).}
t_{SD - supervisory tone integrator decay time (MT3x7xB).}
Figure 4 - Timing Diagram
t_SA
t_SD
Input
Signal
Envelope
ESt/DStD
V_IH
ACK _VIL
SD
V_IH
V_IL
DTMF Energy
Detect
1/f_ACK
t_PAD
b₀
b₁
b₂
LSB
Figure 5 - ACK to SD Timing
t_DH
b₃
MSB
DTMF Energy
Detect
11
Zarlink Semiconductor Inc.