The natural filtering of the sigma-delta ADC combined with the excellent linearity and sensitivity of the analog chain reaches an unprecedented level of performance and integration. The main advantages over techniques from the legacy super-heterodynes up to the now mainstream direct sampling is that the whole receiver chain is well protected against out of band blockers while still relaxing the RF filtering constraints, making it simple and cost effective. The data is then scaled to 16bit and sent to the Micro-Controller for streaming over USB. The final signal at the output has 18bit resolution and an alias rejection performance of 108 dBc.
After every stage, the sample rate is reduced and the resolution increased. Once the IF signal is digitalized, the high sample rate I/Q stream is then frequency translated and processed with cascaded CIC and FIR decimation stages.
This advanced technique adjusts the sampling rate depending on the tuning frequency with the goal of avoiding the disturbances and spurs generated by the switching discrete-time sections of the IF-ADC. The IF-ADC sampling rate is determined by a control algorithm running in the embedded DSP. The IF analog to digital converter (ADC) is a 4th order multi-bit noise shaping topology it features very high dynamic range and linearity. The low-IF signal is then converted into the digital domain by the same IF ADC used in the HF chain.Įxtended VHF coverage is assured by a second Band-III tuner up to 260 MHz, but with reduced performance. The RF signal is converted to baseband by a high linearity passive mixer with a polyphase harmonic rejection structure. The amplifier gain is switchable in 3 dB-steps and fully controlled by the AGC running in the DSP. VHF TunersĮxcellent FM performance is also achieved by using optimized signal paths composed of band filters, high linearity LNAs with a stepped AGC, a polyphase harmonic rejection mixer and IF filters optimized for the FM broadcast bands. The output of the IF-filter is then digitalized by a high dynamic range sigma delta IF ADC for further signal processing in the digital domain. Harmonic rejection is a key issue in wide band HF receivers because of the large input signal bandwidth of the input signal.
#Rf isolator ham radio software#
The 6 dB-stepped AGC gain is fully controlled by the software running in the DSP which optimizes the gain distribution in real time for optimal sensitivity and linearity. The server software is highly scalable and can run on computers as small as the $7 Orange Pi Zero to top end 64bit servers with multiple cores/cpus, including the popular Raspberry Pi series.Īirspy HF+ achieves excellent HF performance by means of a low-loss preselection filter, high linearity LNA, high linearity tunable RF filter, a polyphase harmonic rejection (HR) mixer that rejects up to the 21st harmonic and multi-stage analog and digital IF filtering. You get actual IQ data you can process with your plugins and extract the last bit of information out of it. No compromises in the quality were made like it is usually done in Web SDR interfaces. We concentrated state of the art DSP and networking techniques into our SpyServer software to allow multiple users to stream high quality IQ data from the same receiver at the same time. State of the Art SDR streaming technology! The Airspy HF+ is ultimate solution to Make HF Great Again!Īudio signal with our Digital Noise Reduction processing:
#Rf isolator ham radio portable#
With its best in class strong signal handling capability, the HF+ is the ideal companion for light portable high performance operation.īoth the architecture and level of integration achieved in this design allow us to bring top performance reception at a very affordable price.Īll the major SDR software is supported. But unlike the current offerings in the market, it also brings more frequency agility by using high performance passive mixers with an excellent polyphase harmonic rejection structure. Like most high-end HF receivers, the HF+ uses very high dynamic range ADC’s and front-ends. It is a joint effort between Airspy, Itead Studio and ST Microelectronics to build a state of the art SDR for HF and FM bands. We also provide a high performance extension for weak-signal wide band reception on HF – something other competing solutions fail to address efficiently.Īirspy HF+ is a paradigm shift in high performance HF radio design. Today we offer the best wide band receivers which address these needs. The Software Defined Radio revolution brought great flexibility in VHF and UHF reception.
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