Airspy HF+ Discovery 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.

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. Harmonic rejection is a key issue in wide band HF receivers because of the large input signal bandwidth of the input signal.
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.
Building on the proven Airspy HF+ architecture, Airspy have designed the Most Refined HF/VHF SDR with world class performance in the smallest form factor.
The Airspy HF+ Discovery sets a new standard in terms of reception performance with extra pre-selectors for all the supported bands and a New DSP Core to optimize the gain distribution and the filtering parameters in real-time and dig deeper in the noise.
The signal path includes very high dynamic range data converters along with high performance passive mixers with an excellent Polyphase Harmonic Rejection structure. The included band-tracking pre-selectors eliminate unwanted interference and preserve the dynamic range of the receiver. With its world class strong signal handling capability and incredibly Low Noise, the HF+ Discovery is the ideal companion for All your High Performance Receive Scenarios.
Both the architecture and level of integration achieved in this design allow Airspy to bring top performance reception at a very affordable price.