Ultra small, low power audio receiver + speaker system

[podoljano]

Hi guys, i am working on a design for my upcomming final year project. In a part of this project i have to build a audio receiver but the criteria is quite demanding:
- It has to be able to receive a wireless signal from a source which is going to be 15 cm away, and transmit at max 100mW power
- The audio transmission will be from 200hz to 3kHz
- It has to play the sound on a tiny loudspeaker at round 30-40mW
- It has to work in a envioment with high magnetic radiation of 1Mhz
- The receiver can not use more than 1.5cm x 2cm pcb area.
- receiver can max use 80mW of power

I have been researching different kinds of radio receivers, especially the nordic low power radio receivers. But the problem of digital receivers is that they need need a DAC to convert the digital stream to analog signal for the loudspeaker, plus all the voltage regulation and so on. That really makes it hard to fit in such a small PCB area.

Is there anybody who knows any integrated low power radio receivers with integrated DAC's?
Will a analog audio transmission be better to use taken the space constrains to account?
Is it possible to do audio transmission in the Ghz range since the antenna has to be tiny?

any other ideas are mostly welcome

 

[sky_123]

Hi,

Analog should be easy. An FM transmitter takes less than 1cm square of space. An FM receiver can easily fit your 1.5x2cm range too. There are some very tiny FM ics that were probably intended for mobile phones, maybe silabs parts. I doubt you need much of an antenna for a 15cm range. You could also consider an optical transmission instead of radio.