Description:
This demonstration
project was designed to prove out a wide range, high
resolution hetrodyned RF source concept. Using two PLL's and
a DDS synthesizer this source has 1 Hz resolution over the
full 2 to 250 MHz output range. The PLL modules are 500 to
750 MHz, VCO based designs that are hetrodyned to get the
output frequency range. Excellent phase noise and spurious
response performance is also achieved using the DDS driven
PLL approach. Also included in the design is a novel output
leveling circuit which provides -15 to 15 dB output range
with 0.5 dB accuracy over the entire frequency range. The
source is really a virtual instrument with all it's
functions being controlled by a PIC Microcontroller via an
ActiveX enabled PC control program. Communications to the PC
is via a speedy 19.2 k Baud RS232 link operating in a 4 byte
packet mode for speed reasons.
- 2-250 MHz output range
with 1 Hz resolution.
- -15 to +15 dBm output
range (leveled).
- Full frequency and
output amplitude e-calibration built in.
- PC Control via an
ActiveX enabled virtual front panel.
- RS232 communication (or
USB) link to the PC.
- On board PIC
Microcontroller.
- Spurious responses below
-60 dBc.
- Harmonics below -40
dBc.
- Phase noise = -96 dBc/Hz
at 10 kHz offset.
- Wide band signal path,
no switching from 2-250 MHz (7 octaves).
- Shielded, modular
design.
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