Update on Opera 16Khz (ROS Data mode)
Tx/Rx path design notes
Its noted that linearity may be a problem with Tx drive and Rx , use being made of the `Q' of RF path components to restore envelope shape.
Please note , that both the Opera 16K and base band 1.5 KHz systems will function quite normally with a non linear recovered signal , A square wave is quite sufficient , there being no need for pre filtering of the recovered signal , the DSP engine will perform this task un aided.
If harmonic radiation is not a problem with optical transmission , this may simplify the driver design to a `simple' on/off switch functioning at the audio drive frequency , minimising requirements for Opera Beacon or ROS-Data transmitter
A 16 Khz version of the ROS-Data mode could be coded if data transmission is of interest. ROS data modem is MFSK phase continuous and is suited to non-liner systems.