From 67fa25e5128dc0acbb7acb850b846367c0c19b40 Mon Sep 17 00:00:00 2001
From: Mandar Chitre <mandar@nus.edu.sg>
Date: Wed, 9 Aug 2023 00:37:59 +0800
Subject: [PATCH] fix(dsp): upconvert and downconvert matrix return matrix
 (#38)

---
 src/dsp.jl       |  7 ++-----
 test/runtests.jl | 10 ++++++++++
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/src/dsp.jl b/src/dsp.jl
index baf6532..a65864d 100644
--- a/src/dsp.jl
+++ b/src/dsp.jl
@@ -123,7 +123,7 @@ end
 function upconvert(s::AbstractMatrix, sps, fc, pulseshape=rrcosfir(0.25, sps); fs=framerate(s))
   mapreduce(hcat, eachcol(s)) do x
     upconvert(x, sps, fc, pulseshape; fs=fs)
-  end
+  end[:,:]
 end
 
 """
@@ -143,7 +143,7 @@ end
 function downconvert(s::AbstractMatrix, sps, fc, pulseshape=rrcosfir(0.25, sps); fs=framerate(s))
   mapreduce(hcat, eachcol(s)) do x
     downconvert(x, sps, fc, pulseshape; fs=fs)
-  end
+  end[:,:]
 end
 
 """
@@ -499,11 +499,9 @@ function _istft(iX::AbstractMatrix{T}, nfft::Int, noverlap::Int, window::Union{F
   # H. Zhivomirov, TEM Journal, Vol. 8, No. 1, pp. 56-64, 2019.
   (window === nothing) && (window = rect)
   win, norm2 = Periodograms.compute_window(window, nfft)
-
   nstep = nfft - noverlap
   nseg = size(iX, 2)
   outputlength = nfft + (nseg-1) * nstep
-
   iX .*= win
   x = zeros(T, outputlength)
   normw = zeros(eltype(win), outputlength)
@@ -511,7 +509,6 @@ function _istft(iX::AbstractMatrix{T}, nfft::Int, noverlap::Int, window::Union{F
       @views x[1+(i-1)*nstep:nfft+(i-1)*nstep] .= x[1+(i-1)*nstep:nfft+(i-1)*nstep] .+ iX[:,i]
       @views normw[1+(i-1)*nstep:nfft+(i-1)*nstep] .= normw[1+(i-1)*nstep:nfft+(i-1)*nstep] .+ win .^ 2
   end
-
   trimlength = nfft % 2 == 0 ? outputlength - nfft : outputlength - nfft + 1
   (sum(@view(normw[1+nfft÷2:end-nfft÷2]) .> 1e-10) != trimlength) && (
     @warn "NOLA condition failed, STFT may not be invertible")
diff --git a/test/runtests.jl b/test/runtests.jl
index 89ca848..a2835b8 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -432,6 +432,16 @@ end
   @test framerate(z) == 100
   @test amp2db(rms(x-z)/rms(z)) < -40.0
 
+  x = x[:,1:1]
+  y = upconvert(x, 10, 100)
+  @test nchannels(y) == 1
+  @test framerate(y) == 1000
+  @test y isa AbstractMatrix
+  z = downconvert(y, 10, 100)[12:end-11,:]
+  @test nchannels(z) == 1
+  @test framerate(z) == 100
+  @test z isa AbstractMatrix
+
   x = rcosfir(0.25, 10)
   @test length(x) == 221
   @test x[1:10:end] ≈ vcat(zeros(11), 0.326598866403003, zeros(11))