[hpsdr] Angelia_v5.5 download package

[Joe Martin]

All, 

An Angelia_v5.5 download package is available for download at: 

http://k5so.com/HPSDR_downloads.html

This version of firmware for Angelia-based radios upgrades the firmware design from Quartus II v13.1 to Quartus Prime Lite v16.0, including upgrades of all megafunctions in the design. The 122.88MHz VCXO lock feature is reworked to operate at 10MHz vs the previous 80KHz which in turn allows removal of one of the previous PLLs, the new PLLs are improved megafunction versions that exhibit lower output noise.  This firmware also removes an unnecessary PTT input in the firmware that had potential for creating audio pops/clicks on Rx-to-Tx transitions.  Details of the changes are listed in the Angelia release notes included in the download package, as is the Quartus source code archive file for the firmware. 

Thanks, Warren NR0V, for alerting me to the PTT/audio issue!  

73, Joe K5SO