S E T U P F O R M
C H A P T E R 4
Radio Model
Figure 65: Radio Model Selection
Use this selection to choose the hardware (if any) that is connected to the computer running the
PowerSDR software. When the FLEX-5000 is selected, the center block shows its configuration.
Displayed are the radio model and serial number, the firmware version and the serial numbers of the
various internal circuit boards, except the ATU, which if installed is just marked as “Present”.
DDS
Figure 66: DDS
DDS Stands for Direct Digital Synthesis. The DDS chip in the FLEX-5000 produces an analog sine wave
at up to micro Hertz resolution. The DDS is used as a local oscillator to tune the radio.
Clock Offset:
Allows software corrections to be made manually if the DDS clock oscillator is
not running at exactly 500MHz. Changing the clock offset will change the frequency calibration
of your radio. Typically there will be no need to do so as the radio has been completely factory
calibrated. However, as the radio ages, the oscillator frequency may change slightly.
o
To adjust the frequency calibration of your radio, first use the automatic Frequency
Calibration controls described on page 87.
o
To manually adjust the frequency calibration of your radio, start the internal signal
generator by opening the Setup Form, Tests Tab (page 129) and checking
Enable HW
Signal Generator
. Select
DSB
mode and tune VFO A to the desired frequency. With
SPLT
turned off you should see a -25 dBm signal at the VFO frequency. Change the
display to the Phase display and you will see a single dot. Next, go to the Setup Form -
General Tab, Hardware Config Sub-Tab and check
Expert
to reveal Figure 66 above.
Adjust the Clock Offset control until the dot in the phase display is (almost) standing
still. Don't forget to turn the internal signal generator off, when you are done.
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2003-2008 FlexRadio Systems
