view man/man1/ramp.1 @ 0:5242703e91d3 tip

Initial checkin for AIM92 aimR8.2 (last updated May 1997).

.TH RAMP 1 "1 September 1993"

.SH NAME
ramp \-    generate an exponential sawtooth waveform

.SH SYNTAX 
ramp [options]

.SH 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.

.SH 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:

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

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.

.SH EXAMPLES

1. Growing exponentials

.nf
	    ramp polarity=ramp dec=1ms
.fi

2. Decaying exponentials

.nf
	    ramp polarity=damp dec=1ms
.fi

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

.nf
	    ramp polarity=damp dec=1ms dur=4ms
.fi

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.

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

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.

.nf
	    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
.fi

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

.nf
    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
.fi

7. Modulating white noise with a ramped exponential.

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

.SH "SEE ALSO"
options tone ptrain noise

.SH COPYRIGHT
.LP
Copyright (c) Applied Psychology Unit, Medical Research Council, 1995
.LP
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.
.LP
The MRC makes no representations about the suitability of this 
software for any purpose.  It is provided "as is" without express or 
implied warranty.
.LP
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.