First Post - Audio Engineer needing advice for multiple short range RF links

Hi Nicholas,
Sorry for the delayed response here. I have assigned this request internally and you should get a response within the near future.

Best Regards
Joakim

Thank you Joakim.

Nicholas

Hi Nicholas, 

1) Only 4 units can operate within the same space. Although I've seen some other techniques with "user RF channels" and also multi-channel CC85xx. 

You can use up to 4 slave devices in each star network. But we have successfully tested up to 4 networks working in close proximity.  

2) 10.6 msec latency is the absolute lowest latency possible with legitimate audio quality (using SLAC)

Correct (48 kHz sample rate).

3) A circuit like the reference design running in autonomous mode yet without the range extender give me these limitations?

Not sure what limitations you refer to here. Some more info would help me to answers this.

4) Am I on the wrong path?

A system like this could be implemented using PPW, if this is what you mean by wrong path.

If you elaborate a bit more on these questions I will gladly give more input if needed!

Regards,
Johan 

Hello Johan,

Thank you for your help - truly apprecicated!  A few answers to your questions and a few more questions of my own.

A circuit like the reference design running in autonomous mode yet without the range extender give me these limitations?

Not sure what limitations you refer to here. Some more info would help me to answers this.

* The limitations I'm referring to are in reference to the amount of transmitters/receivers and if having multiple receivers within close proximity would saturate the RF in some way by using the range extender as suggested in the reference design.  Does adding a microprocessor like MSP430 give significant advantages in relation to RF performance over just autonomous mode?

Am I on the wrong path?

A system like this could be implemented using PPW, if this is what you mean by wrong path.

**This was in reference to if the CC85XX solution reference design was the right solution for my intended application (short range, mono audio). Also, are you suggesting that by using PPW I could conceivably operate more than 4 units at once? And could you explain thee "star configuration" you alluded to?

Extra Questions:

- For lowest latency which involves using the SLAC, do I need a proper ADC/DAC like 3101 and PCM5102, respectively or is this handled in the CC85XX

- If used with an analog input source (microphone), must I provide pre amplification when used alone with the CC85XX or does this also require the features with a ADC like 3101?

Thank you again Johan for your help and time,

Nicholas

Hi Nicholas,

Thank you for the clarification!

I ahve some more answers for you:

A circuit like the reference design running in autonomous mode yet without the range extender give me these limitations?

Not sure what limitations you refer to here. Some more info would help me to answers this.

* The limitations I'm referring to are in reference to the amount of transmitters/receivers and if having multiple receivers within close proximity would saturate the RF in some way by using the range extender as suggested in the reference design.  Does adding a microprocessor like MSP430 give significant advantages in relation to RF performance over just autonomous mode?

To add a host MCU and running the CC85xx in host-controlled mode give more advantages from an application perspective rather than a RF performance perspective. What you can do in host-controlled mode is e.g. to manually set the RF channels to use if you know that you have a interferer in a specific part of the spectrum, but apart from some configuration like that, the robustness would be the same using between the different modes of operation. 

 

Am I on the wrong path?

A system like this could be implemented using PPW, if this is what you mean by wrong path.

**This was in reference to if the CC85XX solution reference design was the right solution for my intended application (short range, mono audio). Also, are you suggesting that by using PPW I could conceivably operate more than 4 units at once? And could you explain thee "star configuration" you alluded to?

Each PPW master can connect to 4 slave devices in a star network configuration meaning that the communication is only between master and slave (no slave to slave communication). It is possible to have more than one network in close proximity, but you cannot have any transmissions between the networks. E.g. if you have 2 master devices in the "central unit" they can together get input from 8 slave devices. 

 

Extra Questions:

- For lowest latency which involves using the SLAC, do I need a proper ADC/DAC like 3101 and PCM5102, respectively or is this handled in the CC85XX

The SLAC compression and de-compression is done internally in the CC85xx, so what you need is a "regular" codec with I2S PCM inpout/output.

- If used with an analog input source (microphone), must I provide pre amplification when used alone with the CC85XX or does this also require the features with a ADC like 3101?

The CC85xx only have I2S inputs, so an analog input source would have to go through some kind of a codec. 

Regards,
Johan

Johan,

 Is there a way to implement streaming audio at sub-1GHz, let's say with CC1101 and proprietary protocol?  I would guess that this would minimize the latency time?

~Leonard

 

Hi Leonard,

This is somewhat outside my area of knowledge, I suggest you post a question at the forum for our sub-1 products :

Regards,
Johan