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##

Function: `make_filters()`

0
`void make_filters(float m1, float m2, float *ch1, float *ch2,
float fstart, int n, float srate, int *filled, float *t_coal, int err_cd_sprs, int order)`

This function is an even more stripped down chirp generator, which
fills a pair of arrays with waveforms for an inspiraling binary. The
two chirps differ in phase by radians and are given by
Eqs.() and (). This routine assumes
spinless masses, and computes a chirp with phase corrections
up to a specified post-Newtonian order.
The arguments are:

`m1`: Input. The mass of body-1 in solar masses.
`m2`: Input. The mass of body-2 in solar masses.
`ch1`: Output. Upon return, `ch1[0..filled-1]` contains
the 0-phase chirp. The remaining array elements `ch1[filled..n-1]` are set to zero.
`ch2`: Output. Upon return, `ch2[0..filled-1]` contains
the -phase chirp. The remaining array elements
`ch2[filled..n-1]` are set to zero.
`fstart`: Input. The starting gravity-wave frequency of the
chirp in Hz. Note: this is twice the orbital frequency!
`n:` Input. The length of the arrays `ch1[]` and `ch2[]`.
`srate`: Input. The sample rate, in Hz. This is
where is the time interval between successive entries in
the `ch1[]` and `ch2[]` arrays.
`filled`: Output. The number of
of time steps actually computed, before the chirp calculation was
terminated, or until the arrays were filled (hence
). Thus, on return, only the array elements ` ch1[0..filled-1]` and `ch2[0..filled-1]` are contain the chirp;
the remaining array elements are zero-padded.
`t_coal:` Output. The time to coalescence measured from
the first point output, in `ch*[0]`.
`err_cd_sprs`: Input.
Error code suppression. This integer specifies the level of disaster
encountered in the computation of the chirp for which the user will be
explicitly warned with a printed message. Set to `0`: prints
all the termination messages. Set to `4000`: suppresses
all but a few messages which are harbingers of true disaster. (See
identical argument in `chirp_filters()`.
`order`: Input.
The order of the post-Newtonian approximation. This ranges from 0
(quadrupole approximation) up to 5 (2.5 post-Newtonian order).
Setting `order=4` gives second post-Newtonian chirps.
Technicaly, `order` is the power in past the quadrupole
approximation to which the post-Newtonian expansion is taken.

This routine assumes that you have already allocated storage arrays for
the chirps. Note that the coalescence time may be much later than the last
non-zero entry written into the `ch1[]` and `ch2[]` arrays.

- Author:
Bruce Allen, ballen@dirac.phys.uwm.edu
- Comments:
None.

** Next:** Stationary phase approximation to
** Up:** GRASP Routines: Gravitational Radiation
** Previous:** 2.5 Post-Newtonian corrections to
** Contents**
Bruce Allen
2000-11-19