Designing an AM Transmitter on VLSI: Challenges and Considerations

[hananl]

Hi,
I need to design an AM transmitter as a vlsi project (it needs to be
located on smart dust later on).
Does anyone have any good suggestions were to start from? I am familiar
with vlsi, but don't really know how to implement such a big idea, into
a vlsi simulation and circuit design.
Looking on trasmitter's schemes didn't help, 'cause that's all
resistors, amplifiers and capacitors. How do I translate it into vlsi
design?
some words about specifications:
generally, it's for smart dust, so the power is very low, around
several mili volts, frequecny:
An amplitude modulated signal for typical AM broadcasts consists of a
sinusoid with a frequency in a range from 0.535 MHz to 1.604 MHz having
an amplitude
that is varied (modulated) by an audio signal with frequencies of 20 Hz
to 5KHz.
Be very glad to any guidance...
Thanks

 

[es1]

so the power is very low, around several mili volts

Is several mili-volts a typo of several mili-watts? As in 1s of mW?

I admit I have no idea what smart dust is but I hope your transmitter either has a very short range requirement or is paired with one fine receiver. :)

 

[es1]

http://en.wikipedia.org/wiki/Smartdust

Are you going to try to build a device that is the size of a grain of sand!

Bagnold defines sand as any particle between .02 mm and 1.0 mm in diameter, while Ahlbrandt (1979) uses the range of .1 mm to 1.6 mm.

http://www.nps.gov/archive/whsa/Sand%20Dune%20Geology.htm

That is a challenging package requirment, even if it doesn't include the power source and antenna.

 

[berkeman]

Hi,
I need to design an AM transmitter as a vlsi project (it needs to be
located on smart dust later on).
Does anyone have any good suggestions were to start from? I am familiar
with vlsi, but don't really know how to implement such a big idea, into
a vlsi simulation and circuit design.
Looking on trasmitter's schemes didn't help, 'cause that's all
resistors, amplifiers and capacitors. How do I translate it into vlsi
design?

An AM transmitter is an analog circuit, not a Very Large Scale Integrated circuit (VLSI). You might have a little digital logic involved in the encoder, but you'd generally use analog cells for the modulator and TX amp. You should be able to make a 1MHz AM transmitter with only a few dozen transistors on your ASIC.

BTW, RF dust uses frequencies in the GHz, not 1MHz. Quiz question -- why?