[hpsdr] Janus Rev B Update

[vk4str]

Hi Lyle,

Nice job! However, as I have discussed before with Phil_H, this design 
may not be full duplex capable, ie useable to work a satellite 
transponder. I understand that PWM has certain limitations, please 
correct me if I am wrong.

The AK5394A is used for RX and the processed audio is output on the 
speaker or headphone of the TLV320AIC23B.

The TX audio is fed to the MIC input of the TLV with the only TX output 
option being PWM. The Line-out cannot be used if the speaker is in use.

Would a DAC for TX output not be a better option? I somehow dont trust 
that the PWM option will be satisfactory for TX.

73, Helmut VK4STR


Lyle Johnson wrote:
> ***** High Performance Software Defined Radio Discussion List *****
> 
> The untested Janus Rev B design is ready for review.  It may still have 
> some significant changes pending results of testing.  The AK5394A ADC 
> sample chip is at FedEx enroute to the Land of Oz for Phil H to connect 
> and test.
> 
> In the meantime, you might like to see what's up with the proposed design.
> 
> The basic changes are:
> 
> 1) ADC changed from Cirrus CS5381 to AKM AK5394A.  There are numerous 
> minor changes that resulted from this.  The input op amps are shown as 
> LT parts, but many other less expensive, pin compatible parts exist for 
> those of you who like to experiment.
> 
> 2) 1-wire EEPROM added for ID and configuration.
> 
> 3) PCB layout cleanup.
> 

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