phs

Obtains the phases of a complex-number array

This opcode returns the phases of a complex-number array, as a real-valued array with half the size of its input plus one. The reason for the extra point is to keep the array size equivalent to the output of the mags opcode (which is often used alongside this one).

Syntax

kout[] phs kin[]

Performance

kout[] -- output array containing the phases. It will be created if it does not exist.

kin[] -- input array containing the complex-valued real-imaginary input.

Examples

Here is an example of the phs opcode. It uses the file phs.csd.

<CsoundSynthesizer>
<CsOptions>
-d -o dac
</CsOptions>
<CsInstruments>
/* ksmps needs to be an integer div of
   hopsize */
ksmps = 64
0dbfs=1
nchnls=2


opcode PVA,k[]k[]k,aii
 asig,isize,ihop xin
 iolaps init isize/ihop
 kcnt init 0
 krow init 1
 kIn[] init isize
 kOlph[] init isize/2 + 1
 ifac = (sr/(ihop*2*$M_PI))
 iscal = (2*$M_PI*ihop/isize)
 kfl = 0
 kIn shiftin asig
 if kcnt == ihop then
   kWin[] window kIn,krow*ihop
   kSpec[] rfft kWin
   kMags[] mags kSpec
   kPha[] phs kSpec
   kDelta[] = kPha - kOlph
   kOlph = kPha
   kk = 0
   kDelta unwrap kDelta
   while kk < isize/2 do
    kPha[kk] = (kDelta[kk] + kk*iscal)*ifac
    kk += 1
   od   
   krow = (krow+1)%iolaps
   kcnt = 0
   kfl = 1
 endif
 xout kMags,kPha,kfl
 kcnt += ksmps
endop

opcode PVS,a,k[]k[]kii
 kMags[],kFr[],kfl,isize,ihop xin
 iolaps init isize/ihop
 ifac = ihop*2*$M_PI/sr;
 iscal = sr/isize
 krow init 0
 kOla[] init isize
 kOut[][] init iolaps,isize
 kPhs[] init isize/2+1
 if kfl == 1 then
  kk = 0
  while kk < isize/2 do
    kFr[kk] = (kFr[kk] - kk*iscal)*ifac
    kk += 1
  od
  kPhs = kFr + kPhs
  kSpec[] pol2rect kMags,kPhs
  kRow[] rifft kSpec
  kWin[] window kRow, krow*ihop
  kOut setrow kWin, krow
  kOla = 0
  kk = 0
  until kk == iolaps do
   kRow getrow kOut, kk
   kOla = kOla + kRow
   kk += 1
  od
  krow = (krow+1)%iolaps
 endif
 xout shiftout(kOla)/iolaps
endop

instr 1

 ihopsize = 256  ; hopsize
 ifftsize = 2048 ; FFT size 
 kFreqsOut[] init ifftsize/2+1 ; synthesis freqs
 kMagsOut[] init ifftsize/2+1 ; synthesis mags

 a1 diskin2 "fox.wav",1,0,1 

 kMags[],kFreqs[],kflg PVA a1,ifftsize,ihopsize

 if kflg == 1 then
 ki = 0
   kMagsOut = 0
  kFreqsOut = 0
  iscal = 1.5
 until ki == ifftsize/2 do
   if ki*iscal < ifftsize/2 then
     kFreqsOut[ki*iscal] = kFreqs[ki]*iscal
     kMagsOut[ki*iscal] = kMags[ki]
   endif
    ki += 1
  od
 endif

 a2 PVS kMagsOut,kFreqsOut,kflg,ifftsize,ihopsize

 a1 delay a1, (ifftsize+ihopsize)/sr
    outs a1, a2
endin

</CsInstruments>
<CsScore>
i1 0 10
</CsScore>
</CsoundSynthesizer>

See Also

Vectorial opcodes

array opcodes

Array-based spectral opcodes

Credits

Author: Victor Lazzarini
NUI Maynooth
2014

New in version 6.04