Advanced Channel Emulator
dBm
Operations Manual
ACE600
45
generated files have the same prefix, but the extension becomes
“.
ACE
”. The converted files are then transferred over the LAN
interface, and stored in flash memory in the ACE. The converted files
are in binary format.
The first line includes two values: the number of sample points,
followed by a space, followed by the resolution of the data values. Each
subsequent line will contain one data value (Multipath files have a
different format. See the Multipath file section). Lines are separated by
a carriage return. An example of a delay file with 3 points is:
3.000001
12.456789
12.456788
12.456787
The ASCII parameter files must have a file extension of ".dat" in order
to be recognized by the conversion program. The SATGEN II satellite
data generation program automatically generates the correct file
extension. User generated files should be created with the .dat
extension also. The first three letters of the file name should be one of
DLY, FRQ, ATN, PHA, WGN, RFF, or MPF to represent delay,
frequency offset, attenuation, phase offset, AWGN, RF frequency, and
multipath fading files. Up to 7 alphanumeric characters, including the
underscore
character “_”
can follow the first three letters in the file
name.
Da ta File De s c rip tio n
De la y File s
The ACE9600 changes delay linearly over the update period. The delay
change does not cause phase discontinuities. The change in delay
between two adjacent data points must not require the delay to slew at a
rate greater than 2 msec/sec, nor less than a rate of 0.5 psec/sec. The
delay slew rate is dependent on both the change in delay and the update
period. And the available delay resolution is also dependent on both
parameters. The ACE9600 computes the required delay slew rate from
point to point such that there is constant linear change that occupies the
entire update period. For example, if the update rate is 10 msec, and the
change in delay values is 10 nsec, then the resulting delay slew rate will
be {10 nsec/10msec} or 1 usec/sec. If the same data file is operated at
a 100 msec update rate, the resulting slew rate will be 100 nsec/sec.
In all cases,
•
Each data line consists of 10 to 14 characters, depending on
resolution, including a decimal point
•
Units are ms
Achievable resolution is based on the selected update rate. The range of
delay step size as a function of update rate is given in the table below.
