Update vocoder

docs/lit/examples/01-overview.jl

@@ -3,9 +3,6 @@
 
 This page illustrates the Julia package
 [`Sound`](https://github.com/JeffFessler/Sound.jl).
-
-This page was generated from a single Julia file:
-[01-overview.jl](@__REPO_ROOT_URL__/01-overview.jl).
 =#
 
 #srcURL
@@ -29,31 +26,22 @@ was to provide a simple way to hear audio signals in Julia.
 S = 8192 # sampling rate in Hz
 x = 0.7*cos.(2π*(1:S÷2)*440/S)
 y = 0.8*sin.(2π*(1:S÷2)*660/S)
-sound(x, S) # monophonic
+isinteractive() && sound(x, S) # monophonic
 
 # stereo:
-sound([x y], S)
+isinteractive() && sound([x y], S)
 
 # scale to unit amplitude:
-soundsc([x y], S)
+isinteractive() && soundsc([x y], S)
 
 
 # Using `SampleBuf` may provide some convenience.
 
 S = 8192 # sampling rate in Hz
-x = 0.7*cos.(2π*(1:S÷2)*440/S)
-y = 0.8*sin.(2π*(1:S÷2)*660/S)
+x = 0.7 * cos.(2π*(1:S÷2)*440/S)
+y = 0.8 * sin.(2π*(1:S÷2)*660/S)
 sb = SampleBuf([x y], S) # stereo data
-sound(sb)
-
-
-# ### Reproducibility
-
-# This page was generated with the following version of Julia:
-
-io = IOBuffer(); versioninfo(io); split(String(take!(io)), '\n')
-
+isinteractive() && sound(sb)
 
-# And with the following package versions
 
-import Pkg; Pkg.status()
+include("../../../inc/reproduce.jl")

docs/lit/examples/02-vocoder.jl

@@ -1,11 +1,10 @@
 #=
 # [Phase Vocoder](@id 02-vocoder)
 
-This page illustrates the phase vocoder feature of the Julia package
+This page illustrates the
+[phase vocoder](https://en.wikipedia.org/wiki/Phase_vocoder)
+feature of the Julia package
 [`Sound`](https://github.com/JeffFessler/Sound.jl).
-
-This page was generated from a single Julia file:
-[02-vocoder.jl](@__REPO_ROOT_URL__/02-vocoder.jl).
 =#
 
 #srcURL
@@ -18,6 +17,7 @@ This page was generated from a single Julia file:
 using Sound: phase_vocoder, soundsc, hann
 using DSP: spectrogram
 using MIRTjim: jim, prompt
+using Plots: plot
 using InteractiveUtils: versioninfo
 
 
@@ -36,35 +36,47 @@ to stretch time (by the default factor of 2).
 
 S = 8192*2^2
 x1 = cos.(2π*400*(1:2S)/S) .* hann(2S)
-x2 = cos.(2π*300*(1:S)/S).^3 .* hann(S) # nonlinearity for harmonics
-x = [x1; x2] # 2-note song
+x2 = cos.(2π*300*(1:S)/S) .* hann(S)
+x3 = cos.(2π*500*(1:S)/S).^3 .* hann(S) # nonlinearity for harmonics
+x = [x1; x2; x3] # 4-note song
 y = phase_vocoder(x, S)
 length(x), length(y)
 
 # spectrograms
 sx = spectrogram(x / maximum(abs, x); fs=S)
 sy = spectrogram(y / maximum(abs, y); fs=S)
 dB = x -> max(log10.(x), -10)
-fun = (s) -> jim(s.time, s.freq, dB.(s.power)', aspect_ratio=:auto,
-    ylims = (0,1800), color=:viridis, clim = (-10,0),
-    yticks = 0:300:1800, yflip=false,
-    xlabel="time", ylabel="freq",
+fun = (s) -> jim(s.time, s.freq, dB.(s.power)', aspect_ratio = :auto,
+    color = :viridis, clim = (-10,0), yflip = false,
+    yaxis = ("freq", (0,1800), 0:300:1800),
+    xlabel="time",
     prompt = false,
 )
-jim(fun(sx), fun(sy))
+p0 = jim(fun(sx), fun(sy))
 
 
 # listen to before/after:
-soundsc([x; y], S)
-
-
-# ### Reproducibility
-
-# This page was generated with the following version of Julia:
+isinteractive() && soundsc([x; y], S)
 
-io = IOBuffer(); versioninfo(io); split(String(take!(io)), '\n')
+#=
+The following time plots
+show the original signal
+and the time-stretched version.
+Clearly something is awry.
+=#
 
+p1 = plot((1:length(x))/S, x, label="x(t) original",
+ xaxis = ("t [s]", (0, 4), 0:4),
+ yaxis = ("", (-1, 1), -1:1),
+ size = (600, 300),
+)
+ymax = ceil(maximum(abs, y)) # why not "1" ?
+p2 = plot((1:length(y))/S, y, label="y(t) processed",
+ xaxis = ("t [s]", (0, 8), 0:2:8),
+ yaxis = ("", (-1, 1).*ymax, (-1:1)*ymax),
+ size = (600, 300),
+)
+p12 = plot(p1, p2; layout=(2,1))
 
-# And with the following package versions
 
-import Pkg; Pkg.status()
+include("../../../inc/reproduce.jl")