Session 3 - 15 March 2016

Other sessions

Session 1 : Powering the board, power use, first (bad) trigging and echoes (06 March 2016)
Session 2 : Non-controlled pulsing, inverters, better echoes (11 March 2016)
Session 3 : Getting controlled pulsing, but width not controlled (15 March 2016)
Session 4 : Width of the pulses is getting controlled =) (19 March 2016)
Session 4b : Simple data visualisation with BitScope (19 March 2016)
Session 5 : moving the transducer to get the first image (20 March 2016)
Session 6 : Getting a clinically usable image (28 March 2016)
Session 7 : Getting cleaner images - code improvements (3 April 2016)
Session 8 : Comparing acquisition speeds (3 May 2016)

Getting nicer pulses.

Managed to switch on and off the HV with USPP and USPN.
With a 7.5us wide pulse, we see two echoes separated by 7.5us, hence the double echoes for switching on and off the transducer.

Same setup as Session 1 and Session 2.
The issue is that the two pulses were not controlled.. so we'll need to find something to synchronise these two, with a 150ns delay..

High pulses: from a small pulse, echoes are amplified to a 1.54V , on an average of ~0V.

Tests were done without having put the DAC inputs to GND. That may lead to some issues in reproductibility.
Need to document the role of Jumper 1 more precisely.
Let's try to get images from only 2/3, trigging from an external source? -- Without SPI control of the DAC -- With SPI
We can't get anything at the TP 5/6 signal..