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varpulse (CSound instrument)

This instrument is created by Micheal Mossey.
It is used like this: 
asig varpulse kwidth, kfrq
0 <= kwidth <= 1
Here's an example
The orchestra file: 
sr     = 44100
ksmps  = 2
nchnls = 2

givarpulsetbl_1 ftgen 299, 0, 8193, -7, -1.0, 192, 1.0, 8000, 1.0
givarpulsetbl_2 ftgen 298, 0, 8193, -7, 0.0, 4042, 0.0, 100, -2.0, 4050, -2.0


opcode varpulse, a, kk

	kwidth, kfrq  xin
	koffset = (1-kwidth)/2.0
	aphs	phasor kfrq
	aindx1  = aphs/2.0
	aindx2	= aphs/2.0 + koffset
	asig1	tablei aindx1, givarpulsetbl_1, 1  ; normalized access
	asig2	tablei aindx2, givarpulsetbl_2, 1
	asig	= asig1 + asig2
		xout asig

endop

instr 1
  p3 = p3*1.5

  ilen = p3
  iamp = ampdb(p4)
  ifrq = cpspch(p5)

  kwidth linseg 0, ilen, 1

  kenv linseg 0, 0.02, 1, ilen-0.05, 1, 0.03, 0

  asig varpulse kwidth, ifrq

  outs asig*kenv*iamp, asig*kenv*iamp

endin
The score file: 
i1 0 0.2 70 7.00
i1 + 0.2 72 8.00
i1 + 0.2 74 7.03
i1 + 0.2 76 6.03
i1 + 0.2 78 5.10
i1 + 0.2 80 6.10
i1 + 0.2 82 7.00
varpulse 01 is a similar instrument.