YTD428_07 Datasheet, PDF (17/28 Pages) YAMAHA CORPORATION – IDSU ISDN DSU for Terminal Equipment

DETAILS OF FUNCTIONS
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4.4 T Reference Interface Section
s Reference Power Supply Block
This block provides the electric power to supply for the receiver block and the driver block.
s Receiver Block
The receiver block receives signal from the S/T bus through the external pulse transformer and converts it to
the logic level signal.
The voltage threshold level for he receiver is properly adapted automatically according to the receiving signal
level.
I.430 receive signal ^{+ 0}
(RA/RB)
-0
HRD pin
(TTL level)
LRD pin
(TTL level)
192kHz
(AMI)
(NRZ)
(NRZ)
Figure 4.2 Receive Signal Logic (RDP = “H”, NTSEL = “L”)
s Driver Block
The driver block drives the 2:1 turn ratio transformer according to the logic level transmitting signal.
HTD pin
(TTL level)
LTD pin
(TTL level)
+0
I.430 transmit signal
(TA/TB)
-0
(NRZ)
(NRZ)
192kHz
(AMI)
Figure 4.3 Transmit Signal Logic (TDP = “H”, NTSEL = “L”)