FlexRadio Systems FLEX-6000 Signature Series User Manual

FLEX-6000 Signature Series - SmartSDR for Windows Software User’s Guide
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9 SMARTSDR OVERVIEW
9.1 THEORY OF OPERATION
SmartSDR is a software system designed to run on radios such as the FLEX-6000 Signature Series.
SmartSDR has been designed from the start to work on hardware platforms that perform wide-band
sampling of the RF spectrum. How is wide-band sampling different from other radios?
In superheterodyne (also called “superhet” or “multiconversion”) radio systems, a series of down-
conversions using local oscillators is performed on the RF input ultimately resulting in a baseband
signal. This signal is generally only a few kilohertz wide and is ready to be demodulated and
presented to the operator in the form of audio. In a superheterodyne architecture, generally only a
single receiver is available at a time and the receiver has limited bandwidth.
In a wide-band sampling radio, a large portion of the spectrum is sampled (turned into digital
information) all at once. This sampling provides the basis for the use of several analysis tools and
receivers in the spectrum simultaneously, all from the one hardware sampler.
9.2 KEY SMARTSDR COMPONENTS
9.2.1 Spectral Capture Unit (SCU)
Because the notion of a receiver is firmly established in both the amateur community and possibly
the rest of the world, it seemed inappropriate to describe the functionality of a wide-band sampling
system simply as a “receiver”. Instead, in the SmartSDR world there are one or more “Spectral
Capture Units”, or SCUs, that are responsible for the collection of wide-band data from the RF
spectrum. The SCU components are: an antenna input, an optional set of receive pre-selectors, and
an analog-to-digital converter (ADC). Each SCU in the radio system can be connected to only one
antenna at a time, but due to the sampling architecture it may support multiple receivers and
spectrum displays. The SCU enables listening to multiple bands at the same time on the same
antenna. A hardware platform with multiple SCUs such as the FLEX-6600, FLEX-6600M and FLEX-
6700 allows for monitoring multiple bands on different antennas or the ability to perform more
complex noise mitigation techniques that are available in multi-antenna systems.
9.2.2 Slice Receiver
SmartSDR can create many receivers out of the data collected from the SCU. How does this work?
The characteristics of the SCU sampled data stream vary by radio model but is typically 1-4Gbps of
data that contains all activity across a large section of the RF spectrum. In the FLEX-6700, for
example, an SCU tuned to the HF band collects every signal present in the spectrum from 0-73MHZ!
This data is not directly observable or understandable by an operator, so several tools exist for
understanding and using the SCU data, the first of which is the Slice Receiver. Each Slice Receiver is
tuned to a specific frequency just as a Variable Frequency Oscillator (VFO) would be in a traditional
radio. The Slice Receiver then takes this more manageable amount of data (typically describing 10-
20kHz of the band) and performs operations to output the signals required by the operator.
For example, in the case of a single sideband receiver, the Slice Receiver will demodulate the upper
(or lower) sideband of the data collected, will filter it according to the receiver filter settings, may
perform noise mitigation techniques on the data and then ultimately passes it to an audio system to
become sound for the operator. Because the source of the Slice Receiver data is always the SCU data
and each Slice Receiver uses the same techniques to demodulate, filter and convert the signal into

FlexRadio Systems FLEX-6000 Signature Series Specifications

General

Brand	FlexRadio Systems
Model	FLEX-6000 Signature Series
Category	Transceiver
Language	English