3
rd
Generation Rack-
Mount RDMS™
70
Quasonix, Inc.
Figure 105: Advanced Menu, AFC Mode
–
Hold
4.4.2.21 PCM Encoding
The PCM Encoding setting controls the RDMS receiver output PCM data format. Two primary options are
available: the receiver can convert encoded data to NRZ-L, or it can preserve transmit encoding. The first option
allows conversion of any of the following encoding formats to NRZ-L:
•
NRZ-L: Non-return-to-zero, level
•
NRZ-M: Non-return-to-zero, mark
•
NRZ-S: Non-return-to-zero, space
•
RZ: Return-to-zero
•
Biphase-L: Bi
ϕ
, level
•
Biphase-M: Bi
ϕ
, mark
•
Biphase-S: Bi
ϕ
, space
•
DM-M: Delay modulation (Miller code), mark
•
DM-S: Delay modulation (Miller code), space
•
M2-M: Modified delay modulation (Miller squared code), mark
•
M2-S: Delay modified modulation (Miller squared code), space
The second option allows the transmit encoding to be preserved and output from the RDMS unaltered. To
accomplish this, PCM Encoding must be set to NRZ-L
–
regardless of the actual transmit encoding. Also, for
encoding formats that use di-bits to represent each user bit (i.e., RZ, Bi
ϕ
, DM, or M2), the RDMS bit rate must be
set to twice the user bit rate. Note that the RDMS output clock will clock at twice the user bit rate in this
configuration.
The user may select the PCM Encoding value by pressing the Enter key on the front panel keypad, and then
selecting the appropriate value from the PCM Encoding selection screen, shown in Figure 107.
