Architecture - Apache Labs ANDROMEDA ANAN-7000DLE MKII User Manual

1.2 Architecture
RX2
ant Variable
RF
Atten‐
Filters
uator
Band
Variable
RF
Atten‐
Filters
uator
Band
3
Ant,
T/R
2
Switch
1
Low
Linear
Pass
Amplifier
Filters
Band
1. Your radio hardware provides a transmit/receive path. There are two fully separate RX paths
each with its own signal conditioning, digitising and processing.
2. Received signals are filtered, attenuated then digitised using two high performance
analogue‐to‐digital converter. The A‐D converters cover the whole HF band. Digital
processing in the Field Programmable Gate Array (FPGA) converts a part of the HF band to
zero centre frequency, and transfers the data to the PC via Ethernet. The bandwidth
provided can be selected, but is usually in the range 48KHz – 1.536MHz.
3. The PC runs the THETIS program. THETIS has two halves: a user interface, and PC based
signal processing.
4. THETIS connects to the receiver data streams and provides further signal processing to
reduce noise, to select the signals of interest and demodulate them. Its user interface
provides a view of the band activity in the downconverted signal is shown, and controls to
tune to the required signal and demodulate it successfully.
5. Received audio is routed to the internal speakers. Additional PC connected speakers are also
possible.
6. On transmit, THETIS provides the initial signal processing to optimise the transmit signal.
Audio processing is available to enhance a voice signal. A CW keyer is provided. Sampled
data is sent to the radio hardware via Ethernet.
7. The radio hardware upconverts the TX signal to the required frequency, sets its signal level,
amplifies and filters it. Amplifier linearization is available: a sample of the signal from the
linear amplifier is downconverted back through the receiver, and compared with the
"intended" TX signal. The difference is processed by THETIS to apply pre‐distortion so that
the final output from the linear amplifier has approximately 20dB lower spurious signal
content that a "normal" HF transmission.
ANDROMEDA Manual
A‐ D Digital
Conver‐ Down‐
ter Convert
VFO
Tune
A‐ D Digital
Conver‐ Down‐
ter Convert
VFO
Tune
Ethernet
Digital
Down‐
Convert
VFO
Tune
D‐A Digital
Conver‐ Up‐
ter Convert
FPGA
VFO
Tune
Audio
Keyer
Codec
Ethernet
2 Channel
Receiver
DSP
User interface
Puresignal
TX Audio
Linear‐
DSP
isation
THETIS on PC
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