# Name that modulation...

Started by July 16, 2008
```Start with logic 0s and 1s.  Convert them to pulses that look
roughly like Gaussian bell curves each going from near-zero to
maximum to near-zero in one bit time, 0s going negative, 1s
going positive.  Use said negative-and-positive-going pulses to
frequency-modulate a carrier.

What is the name of this type of modulation?  If my description
of the mechanics of this modulation scheme is not quite right,
what is the name of the modulation that would produce the same
apparent result as described above?

```
```On 16 Jul, 22:57, "John E. Hadstate" <jh113...@hotmail.com> wrote:
> Start with logic 0s and 1s. &#2013266080;Convert them to pulses that look
> roughly like Gaussian bell curves each going from near-zero to
> maximum to near-zero in one bit time, 0s going negative, 1s
> going positive. &#2013266080;Use said negative-and-positive-going pulses to
> frequency-modulate a carrier.
>
> What is the name of this type of modulation? &#2013266080;If my description
> of the mechanics of this modulation scheme is not quite right,
> what is the name of the modulation that would produce the same
> apparent result as described above?

PCM - Pulse Code Modulation?

Rune
```
```GMSK?
```
```>Start with logic 0s and 1s.  Convert them to pulses that look
>roughly like Gaussian bell curves each going from near-zero to
>maximum to near-zero in one bit time, 0s going negative, 1s
>going positive.  Use said negative-and-positive-going pulses to
>frequency-modulate a carrier.
>
>What is the name of this type of modulation?  If my description
>of the mechanics of this modulation scheme is not quite right,
>what is the name of the modulation that would produce the same
>apparent result as described above?

BPSK with a shaped pulse.

Mark
```
```John E. Hadstate wrote:
> Start with logic 0s and 1s.  Convert them to pulses that look roughly
> like Gaussian bell curves each going from near-zero to maximum to
> near-zero in one bit time, 0s going negative, 1s going positive.  Use
> said negative-and-positive-going pulses to frequency-modulate a carrier.
>
> What is the name of this type of modulation?  If my description of the
> mechanics of this modulation scheme is not quite right, what is the name
> of the modulation that would produce the same apparent result as
> described above?

Band-limited FSK

Jerry
--
Engineering is the art of making what you want from things you can get.
&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;
```
```On Wed, 16 Jul 2008 16:57:50 -0400, "John E. Hadstate"
<jh113355@hotmail.com> wrote:

>Start with logic 0s and 1s.  Convert them to pulses that look
>roughly like Gaussian bell curves each going from near-zero to
>maximum to near-zero in one bit time, 0s going negative, 1s
>going positive.  Use said negative-and-positive-going pulses to
>frequency-modulate a carrier.
>
>What is the name of this type of modulation?  If my description
>of the mechanics of this modulation scheme is not quite right,
>what is the name of the modulation that would produce the same
>apparent result as described above?

It sounds to me like you're describing GMSK.

Eric Jacobsen
Minister of Algorithms
Abineau Communications
http://www.ericjacobsen.org

Blog: http://www.dsprelated.com/blogs-1/hf/Eric_Jacobsen.php
```
```

> Start with logic 0s and 1s.  Convert them to pulses that look roughly
> like Gaussian bell curves each going from near-zero to maximum to
> near-zero in one bit time, 0s going negative, 1s going positive.  Use
> said negative-and-positive-going pulses to frequency-modulate a carrier.
>
> What is the name of this type of modulation?

That looks like Feher's PSK. I.e. phase modulation with the constant
envelope and the smooth transition of the phase.

DSP and Mixed Signal Design Consultant
http://www.abvolt.com

```
```

> Start with logic 0s and 1s.  Convert them to pulses that look roughly
> like Gaussian bell curves each going from near-zero to maximum to
> near-zero in one bit time, 0s going negative, 1s going positive.  Use
> said negative-and-positive-going pulses to frequency-modulate a carrier.
>
> What is the name of this type of modulation?

DAMPS

:)

```
```>It sounds to me like you're describing GMSK.

Or half of a GMSK signal since MSK is derived from OQPSK, and he's
describing binary shifting.

Mark
```
```On Jul 16, 1:57 pm, "John E. Hadstate" <jh113...@hotmail.com> wrote:
> Start with logic 0s and 1s.  Convert them to pulses that look
> roughly like Gaussian bell curves each going from near-zero to
> maximum to near-zero in one bit time, 0s going negative, 1s
> going positive.  Use said negative-and-positive-going pulses to
> frequency-modulate a carrier.
>
> What is the name of this type of modulation?  If my description
> of the mechanics of this modulation scheme is not quite right,
> what is the name of the modulation that would produce the same
> apparent result as described above?

I would say it -is- bipolar Gaussian frequency shift keying, but I
wouldn't say it in public.

Dale B. Dalrymple
```