DS_1x22_017
73M1822/73M1922 Data Sheet
11.5 Trans-Hybrid Cancellation
A Transmit Bit Stream (TBS) emulating a sinusoid of 1 kHz, full scale (code word of +/- 32,767) is applied to
SDIN and the residual signal is measured at SDOUT. Unless stated otherwise, test conditions are: ACZ=00
(600 Ω termination), THEN=1, ATEN=0, DAA=01, TXBST=0. TXM is externally fed back into the Line-Side
Device (73M1912) to effect cancellation of transmit signal.
Table 43: Trans-Hybrid Cancellation
Parameter
Test Condition
Min
Nom
Max
Units
Transmit hybrid
cancellation
Measure RxD in HIC
26
dB
Offset voltage
AC swing
50% 1’s Density
25
0.95
-81
50
mV
Vpk
dBm
1kHz sinusoid at Tip and Ring
300 Hz – 4 kHz at Tip and Ring
0.85
1.05
Idle noise
11.6 Direct Access Arrangement Control Functions
These Transmit Control Registers contain control information to set up the line side of the 73M1x22.
Included are DC-IV characteristics, off-hook control, etc.
Table 44: DAA Control Functions
Function
Mnemonic Location
Register
Type Description
OFH
0x12[7]
WO Off-Hook Enable
This bit controls the state of the Hook signal.
0 = On-Hook. (Default)
1 = Off-Hook.
PLDM
0x13[3]
WO Pulse Dialing Mode Enable
Alleviates the strict timing requirements for the Host having to control
ENDC and OFH during pulse dialing. With PLDM = 1, the Host only has
to toggle OFH to perform pulse dialing.
0 = Pulse Dialing Mode is disabled. (Default)
1 = Pulse Dialing Mode is enabled.
IDISPD
0x13[1:0] WO Discharge and Pulse Dialing
Controls the DC discharge current and how fast the loop turns off. Affects
pulse dialing waveform. Controls the amount of discharge current during
hook switch transitions.
0 = Minimum current. (Default)
1 = Maximum current.
It is recommended to set IDISPD to 1 prior to hook switching operations.
ENNOM
0x12[0]
WO Enable Nominal Operation
0 = Speeds up the on and off hook transitions time by increasing the DC
loop bandwidth of the DC transconductance circuit in the 73M1x22. This
can be used for pulse dialing. In addition, ENNOM=0 prevents the reset
of all bits in Register 0x12. (Default)
1 = Enter Nominal Operation. Reduces the loop bandwidth of the DC
transconductance circuit. Allows reset of Register 0x12 caused by bits
UVDT, OVDT or OIDT.
Rev. 1.6
65
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
