Comtech EF Data DT-4500 Series - Manual (Page 8)

Filename: T_ERRATA
2
Dual IF Rack Mount Converters
Comtech EF Data offers converters with the ability to switch the output IF frequency (Downconverters)
and/or the input IF frequency (Upconverters) from 70 MHz to 140 MHz or vice versa. The actual IF
bandwidth is maintained as the standard
± 18 MHz (± 20 MHz) of the 70 MHz configurations.
The software modification required for the implementation of the IF frequency switching are:
1. A front panel command to allow the output IF to switch from 70MHz to 140.
a. The new selection is located in the “Configuration” menu tree. The “normal”
FREQ/ATT/MUT menu is split into two. First menu screen now has “RF FRE= XXXXX
MHz on top line, with “IF FRE= XXX MHz” and “Rx= XXX” on second line. A second
menu screen contains the attenuator setting.
b. Mute behavior after changing the IF frequency is the same as the normal mute behavior
after changing the RF frequency.
2. A new remote command is implemented to accomplish the identical operation as in (1).
a. Command structure similar to the RF frequency selection.
The default is 70 MHz
Command Details
Set IF Frequency: leading zero.
Confirmation: >DEV/IFF_ xxx'cr''lf'] (where xxx is either 140 or 70 without requiring
leading zero.
Retrieve Frequency: _'cr'
Confirmation: >DEV/IFF_ xxx'cr''lf'] (where xxx is either 140 or 70 without requiring
leading zero.
Mute behavior after changing the IF frequency would be the same as the mute behavior after
changing the RF frequency.
Redundant operation
The customer can not “mix” dual IF converters with standard converters in a redundant system