IC AM DEMODULATOR, Centre Frequency 250kHz

[PaulAnthonyCreaser]

I recently built a simple AM demodulator, centre frequency 250kHz, analogue voice audio using discrete components. I'd like to reduce the component count and if possible use an IC solution with the minimum of external supporting components. Does anyone know of an IC, which could do this?

 

[Audioguru]

Why look for an IC when only a couple of parts will demodulate AM:

 

[PaulAnthonyCreaser]

Yes you are quite right.

I'm basically experimenting with audio transmission over light (VLC) using LEDs. I'm trying out different modulation and demodulation circuits for performance comparisons, noise, distortion etc....

For example:-

1 Non-coherent detection (The AM detector circuit you have above)
2 Coherent detection

Google has been a good source of basic circuit designs and tutorials, so I can successfully transmit and receive audio using an LED.

With regards to a IC solution. I know due to basic physics, larger inductors/coils, capacitors are not possible on an IC, so a single chip is probably not possible. My curiosity is, are there any IC solutions out there. My conclusion so far there are a number of ICs out there, but essentially they won't reduce the component count.

So essentially I'm studying, and experimenting with different designs, hence my curiosity in possible IC solutions.

 

[BradtheRad]

larger inductors/coils

Don't know how much this will help in regard to an inductor... There is the gyrator (or active inductor) made from an op amp and capacitor. It's suitable for light loads.

 

[chuckey]

Try a Google search with " am radio on a chip ", there are a few chips available, loads of gain and with AVC and a detector. I still use a ZN414 as a longwave tuner inside a MW only set, must be 30 years old!
Frank

 

[Audioguru]

At The Dollar Store you can buy a portable FM radio that has pretty poor performance and lots of distortion but it comes with a battery and earphones and costs only one dollar. It uses an FM radio IC TDA7088 invented by Philips but they don't make it anymore. The radios with it today use a Chinese copy of the Philips IC. Many of the inductors have been replaced by opamp active filters on the IC.

There are wireless headphones and conference translation products that use audio that FM modulates Infrared LEDs. They do not use AM because it picks up all kinds of interference and usually sounds awful.