Audio signal project

Hello all experts,

I find Myriad RF modules very much suitable for the audio signal transmission. Has anybody done this before? Can Tx analogue inputs and RX analogue outputs used as audio signal in/out? How can i control transceiver chip externally?

the frequency range covered (input/output) is from 260MHz to 3.8GHz as stated in the site. if that suits you, then probably yes. however what is the modulation BW you need?

I think the control is done through serial interface. Have you donwloaded all the documentation included? It should all be here: http://myriadrf.org/wp-content/uploads/2012/10/MF-LMS6002Dr2-Programming-and-Calibration-Guide-1.1r1.pdf

Thanks bl,

my modulation signal BW should be up to 20kHz (audio signal). I can see from the documentation the BW is quite wide.

It is still not really clear for me how can I use quadrature modulator for transmitting and receiving audio signal. Should I use only I or Q channel or both IQ channels for audio signal input and output?

regarding BW I think the lowest could be around 700kHz and probably might be squeezed down a bit more. if that suites you, then its fine, use at your own risk :slight_smile:

@Stefan

As almost all audio cables are balanced, connect one audio channel to I and another to Q channel on Myriad RF board. This is how it should look in the board:

  1. Audio channel 1 connect to X4 connector pin 1 (TXININ) on Myriad RF board.
  2. Audio channel 2 connect to X4 connector pin 4 ( TXINQN) on Myriad RF board .
  3. And audio cable shield connect to X4 connector pin 3 as a ground.

Some logic have to be used for receiver, only on x5 connector.

I hope that helps.

Andrew.
 

Hi bl and andrewhux

Thanks for your answers… I have already bought 2 Myriad RF boards… Waiting for them to come.

I was just thinking to connect speaker directly with 8 Ohm impedance to analog RX output.

Do you think it is going to work?

@Stefan,

You should be OK connecting the speakers.

Andrew.

Finally I had time to finish my audio signal transmission by using 2 Myriad RF boards. Have a look at the link below. It is really working with pretty good sound quality. You will see all comments what I did and what I got out in the video I made. Hope you will find some ideas too and share your result in the future.
Here is the link to video in youtube:

Here is the link to images I used: block diagram & Tx / Rx analog pins connection (click next)
https://plus.google.com/u/0/photos/113000996243065826697/albums/5839350495209155185/5839350496521973554
Thanks to you all for support.

Well done, Stefan. It really look interesting what you have done. You are connecting audio cable on TX analog input in different I / Q negative / positive combination than the RX analog output. Is there any different on sound volume level or quality in you connect in same combination? For example TxIN: I_N / Q_N and RxOUT: I_N / Q_N, or TxIN I_N / I_P and RxOUT I_N / I_P.

Good question. I thought that it should be, but after I tested different combinations it sounded same volume and quality. There is no different.

I see in the video you are sending clock signal from one Myriad RF board to another. This way the whole systems still works as wireless. Did you tried to send clock for those boards from different signal generators?

Stefan, where did you get the interface from ?

Stefan, where did you get the interface board from ?

You can check up http://www.azio-tw.com/?cat=58 it shows limited stock. I don’t know it still available or not.