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Manual Page - ramp(1)


Manual Reference Pages  - RAMP (1)

NAME

ramp - generate an exponential sawtooth waveform


CONTENTS

Syntax
Description
Options
Examples
Copyright

SYNTAX

ramp [options]

DESCRIPTION

Generate samples of an exponential sawtooth waveform at a given sample rate.
Samples are written on the stdout in binary shorts or floats according to
the ‘type’ option.

OPTIONS

1. period, amplitude, duration.

The ‘period’ option sets the period of repetition of the waveform in samples.
The ‘duration’ option sets the total duration of the output waveform in
samples.
Both may be given with time units (s or ms) in which case the time is converted to
samples using the given ‘samplerate’ option.
The ‘amplitude’ option sets the height of the waveform.

2. polarity

The ‘polarity’ option is used to set the direction of the ramp:

polarity=ramp growing exponential: A.exp(t-T) 0<=t<=T
polarity=damp decaying exponential: A.exp(-t) 0<=t<=T

3. decay

The argument of the exponential is calibrated so that the decay factor is
a half-life period.
The wave grows/decays to half its given amplitude in the given decay time.

EXAMPLES

1. Growing exponentials

         ramp polarity=ramp dec=1ms

2. Decaying exponentials

         ramp polarity=damp dec=1ms

3. Half a cycle of an 8ms decaying exponential.

         ramp polarity=damp dec=1ms dur=4ms

4. Modulating a tone with a damped exponential.
Note: modulating can be done in floating point using a ramp with unit
amplitude, or it can be done in integer arithmetic as below.
The scale factor in the ‘merge’ program is used to avoid 16-bit overflow.

         tone period=.5ms > foo1
         ramp pol=damp dec=1ms > foo2
         merge op=mult factor=0.01 foo1 foo2 > foo3

5. Modulating a tone with a ramped exponential.
The 800Hz tone is modulated with a unit ramped exponential with a 25ms
repetition rate and a 4ms half life.

         tone freq=800Hz amp=10000 type=float > foo1
         ramp pol=ramp period=25ms dec=4ms amp=1 type=float > foo2
         merge op=mult type=float foo1 foo2 | ftos > foo3

6. Modulating a tone with a damped exponential, and half-wave rectifying to
generate damped pulses.

tone period=.5ms amp=500 type=float > foo1
ramp pol=damp dec=1ms amp=1 type=float > foo2
merge op=mult type=float foo1 foo2 | ftos | gate range=min-0 op=0 > foo3

7. Modulating white noise with a ramped exponential.

         noise type=float > foo1
         ramp pol=ramp dec=1ms amp=1 type=float > foo2
         merge op=mult type=float foo1 foo2 | ftos > foo3

SEE ALSO

options tone ptrain noise

COPYRIGHT

Copyright (c) Applied Psychology Unit, Medical Research Council, 1995

Permission to use, copy, modify, and distribute this software without fee
is hereby granted for research purposes, provided that this copyright
notice appears in all copies and in all supporting documentation, and that
the software is not redistributed for any fee (except for a nominal
shipping charge). Anyone wanting to incorporate all or part of this
software in a commercial product must obtain a license from the Medical
Research Council.

The MRC makes no representations about the suitability of this
software for any purpose. It is provided "as is" without express or
implied warranty.

THE MRC DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
THE A.P.U. BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES
OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
SOFTWARE.


SunOS 5.6 RAMP (1) 1 September 1993

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