[hpsdr] Odyssey SDR Rev. B Schematics

[Steven Bible]

Gang,

We've been busy with Odyssey, the SDX for SuitSat-2.  

     http://hpsdr.org/wiki/index.php?title=ODYSSEY

Rev. A Design

The Rev. A SDX PCB's arrived last week.  This weekend I started populating them starting with the power supply first.  I hope to have these fully populated and sent to Bob's N4HY team for DSP programming.

This philosophy behind this design is to use circuitry that we know has been tried and tested.  We wanted a safe low risk design.  The codec is the TLV320AIC23B.  This design is by Joe N9WXU.

Rev. B Design

In the background, I've been working with Ahti's OH2RZ ISD design (which is a progression of Bob N4HY and Phil C's N8VB ISD work - see schematics on the HPSDR SVN and Phil's Blog).  The goal of this circuitry is to design a fully differential circuit for input (ISD) and output (exciter) to create a low-noise circuit and also to get to a signal power supply.  The input (ISD) follows Ahti's work.  I've made a few additions to Ahti's work after reading a number of application notes, and to add a few extra components that we can use at the time of testing (a follow up PCB would be designed from the lessons learned from this board).  We've already had a short discussion of this about a month ago on the HPSDR list (see HPSDR archives).  

On the Odyssey Wiki, I've posted Rev. B schematics.  In this design I've incorporated the changes from the discussion a month ago and added an exciter circuit.  Thanks to Howard Long G6LVB, at the AMSAT Symposium we discovered that we were both working on very similar projects (see STELLA http://www.g6lvb.com/Articles/STELLA/index.htm).  He has a exciter circuit that I've added.  We really need your comments on this circuit.  What would a fully differential exciter look like?  My concern is that the OPA1632 can drive 50 ohms.  But Howard has been successful as he demonstrated his hardware at the 2006 AMSAT Symposium.  

Thanks everyone,

- Steve N7HPR



\r\n- Steve\r\n  (n7hpr at tapr.org)\r\n