Rimmer wrote:
> "senkumar02" <senkumar02@yahoo.com> wrote in message
> news:IoWdnWl2cslNdBDfRVn-jw@giganews.com...
> 
>>hi,
>>i want to take FM modulation to a signal which is changing in its
>>amplitude and frequency. Give me a idea how to start.
>>
>>Thanks,
>>Senthil
>>
>>
>>
>>
>>This message was sent using the Comp.DSP web interface on
>>www.DSPRelated.com
> 
> 
> It is possible to both FM modulate and AM modulate a signal at the same time
> and separate the basband signals.
> The sidebands are I think oothogonal.
> 
> Rimmer

Not in the general case, but with narrow-band FM, they are nearly 
orthogonal, making the combination a form of quadrature modulation. 
(Phase-contrast microscopy works by shifting the phase of the images 
"carrier" 90 degrees with respect to the "sidebands: (diffraction 
pattern), thereby generating image contrast by converting phase 
differences to amplitude differences. In that application, distortion in 
unimportant

Jerry
-- 
Engineering is the art of making what you want from things you can get.
&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;

senkumar02 wrote:

> hi,
> i want to take FM modulation to a signal which is changing in its
> amplitude and frequency. Give me a idea how to start.
> 
> Thanks,
> Senthil
> 
Do you mean you want to take a signal with varying amplitude and 
frequency, and FM modulate a carrier with it?  Or do you mean that you 
want to take a signal with varying amplitude and frequency and apply FM 
modulation to it?

In the first case the answer is "sure!", because it's just plain old FM. 
  In the second case the answer is "probably not", because you've 
already got frequency variation.

-- 
-------------------------------------------
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

"senkumar02" <senkumar02@yahoo.com> wrote in message
news:IoWdnWl2cslNdBDfRVn-jw@giganews.com...
> hi,
> i want to take FM modulation to a signal which is changing in its
> amplitude and frequency. Give me a idea how to start.
>
> Thanks,
> Senthil
>
>
>
>
> This message was sent using the Comp.DSP web interface on
> www.DSPRelated.com

It is possible to both FM modulate and AM modulate a signal at the same time
and separate the basband signals.
The sidebands are I think oothogonal.

Rimmer

senkumar02 wrote:
> hi,
> i want to take FM modulation to a signal which is changing in its
> amplitude and frequency. Give me a idea how to start.
> 
> Thanks,
> Senthil

I've no idea of where to begin. I don't understand "take FM modulation 
to a signal", and you'll need to explain how and why both frequency and 
amplitude change. Since the AM and FM sidebands overlap, there will be 
distortion to a greater or lesser extent.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;&#4294967295;