Rename Filter -> FilterCoefficients

Author: simonster

src/Filters/design.jl

@@ -347,14 +347,14 @@ function transform_prototype(ftype::Bandstop, proto::ZeroPoleGain)
     ZeroPoleGain(newz, newp, proto.k * real(num)/real(den))
 end
 
-transform_prototype(ftype, proto::Filter) =
+transform_prototype(ftype, proto::FilterCoefficients) =
     transform_prototype(ftype, convert(ZeroPoleGain, proto))
 
-analogfilter(ftype::FilterType, proto::Filter) =
+analogfilter(ftype::FilterType, proto::FilterCoefficients) =
     transform_prototype(ftype, proto)
 
 # Bilinear transform
-bilinear(f::Filter, fs::Real) = bilinear(convert(ZeroPoleGain, f), fs)
+bilinear(f::FilterCoefficients, fs::Real) = bilinear(convert(ZeroPoleGain, f), fs)
 function bilinear{Z,P,K}(f::ZeroPoleGain{Z,P,K}, fs::Real)
     ztype = typeof(0 + zero(Z)/fs)
     z = fill(convert(ztype, -1), max(length(f.p), length(f.z)))
@@ -382,5 +382,5 @@ prewarp(ftype::Union(Lowpass, Highpass)) = (typeof(ftype))(4*tan(pi*ftype.w/2))
 prewarp(ftype::Union(Bandpass, Bandstop)) = (typeof(ftype))(4*tan(pi*ftype.w1/2), 4*tan(pi*ftype.w2/2))
 
 # Digital filter design
-digitalfilter(ftype::FilterType, proto::Filter) =
+digitalfilter(ftype::FilterType, proto::FilterCoefficients) =
     bilinear(transform_prototype(prewarp(ftype), proto), 2)

src/Filters/filt.jl

@@ -77,8 +77,8 @@ Base.filt{T,S<:Number}(f::Biquad{T}, x::AbstractArray{S}, si=_zerosi(f, x)) =
     filt!(Array(promote_type(T, S), size(x)), f, x, si)
 
 ## For arbitrary filters, convert to SecondOrderSections
-Base.filt(f::Filter, x) = filt(convert(SecondOrderSections, f), x)
-Base.filt!(out, f::Filter, x) = filt!(out, convert(SecondOrderSections, f), x)
+Base.filt(f::FilterCoefficients, x) = filt(convert(SecondOrderSections, f), x)
+Base.filt!(out, f::FilterCoefficients, x) = filt!(out, convert(SecondOrderSections, f), x)
 
 #
 # filtfilt
@@ -211,7 +211,7 @@ function filtfilt{T,G,S}(f::SecondOrderSections{T,G}, x::AbstractArray{S})
 end
 
 # Support for other filter types
-filtfilt(f::Filter, x) = filtfilt(convert(SecondOrderSections, f), x)
+filtfilt(f::FilterCoefficients, x) = filtfilt(convert(SecondOrderSections, f), x)
 filtfilt(f::PolynomialRatio, x) = filtfilt(coefb(f), coefa(f), x)
 
 ## Initial filter state

src/Filters/response.jl

@@ -4,18 +4,18 @@
 # Frequency response of a digital filter
 #
 
-function freqz(filter::Filter, w::Number)
+function freqz(filter::FilterCoefficients, w::Number)
     filter = convert(PolynomialRatio, filter)
     ejw = exp(-im * w)
     polyval(filter.b, ejw) ./ polyval(filter.a, ejw)
 end
 
-function freqz(filter::Filter, w = linspace(0, π, 250))
+function freqz(filter::FilterCoefficients, w = linspace(0, π, 250))
     filter = convert(PolynomialRatio, filter)
     [freqz(filter, i) for i = w]
 end
 
-function freqz(filter::Filter, hz::Union(Number, AbstractVector), fs::Number)
+function freqz(filter::FilterCoefficients, hz::Union(Number, AbstractVector), fs::Number)
     filter = convert(PolynomialRatio, filter)
     freqz(filter, hz_to_radians_per_second(hz, fs))
 end
@@ -25,7 +25,7 @@ end
 # Phase response of a digital filter
 #
 
-function phasez(filter::Filter, w = linspace(0, π, 250))
+function phasez(filter::FilterCoefficients, w = linspace(0, π, 250))
     h = freqz(filter, w)
     unwrap(-atan2(imag(h), real(h)))
 end
@@ -35,7 +35,7 @@ end
 # Impulse response of a digital filter
 #
 
-function impz(filter::Filter, n=100)
+function impz(filter::FilterCoefficients, n=100)
   i = [1; zeros(n-1)]
   filt(filter, i)
 end
@@ -44,7 +44,7 @@ end
 # Step response of a digital filter
 #
 
-function stepz(filter::Filter, n=100)
+function stepz(filter::FilterCoefficients, n=100)
   i = ones(n)
   filt(filter, i)
 end
@@ -54,18 +54,18 @@ end
 # Frequency response of an analog filter
 #
 
-function freqs(filter::Filter, w::Number)
+function freqs(filter::FilterCoefficients, w::Number)
     filter = convert(PolynomialRatio, filter)
     s = im * w
     polyval(filter.b, s) ./ polyval(filter.a, s)
 end
 
-function freqs(filter::Filter, w::AbstractVector)
+function freqs(filter::FilterCoefficients, w::AbstractVector)
     filter = convert(PolynomialRatio, filter)
     [freqs(filter, i) for i = w]
 end
 
-function freqs(filter::Filter, hz::Union(Number, AbstractVector), fs::Number)
+function freqs(filter::FilterCoefficients, hz::Union(Number, AbstractVector), fs::Number)
     filter = convert(PolynomialRatio, filter)
     freqs(filter, hz_to_radians_per_second(hz, fs))
 end

src/Filters/types.jl

@@ -1,12 +1,12 @@
 # Filter types and conversions
 
-abstract Filter
+abstract FilterCoefficients
 
 #
 # Zero-pole gain form
 #
 
-immutable ZeroPoleGain{Z<:Number,P<:Number,K<:Number} <: Filter
+immutable ZeroPoleGain{Z<:Number,P<:Number,K<:Number} <: FilterCoefficients
     z::Vector{Z}
     p::Vector{P}
     k::K
@@ -16,7 +16,7 @@ end
 # Transfer function form
 #
 
-immutable PolynomialRatio{T<:Number} <: Filter
+immutable PolynomialRatio{T<:Number} <: FilterCoefficients
     b::Poly{T}
     a::Poly{T}
 
@@ -56,7 +56,7 @@ coefa(f::PolynomialRatio) = reverse(f.a.a)
 # A separate immutable to improve efficiency of filtering using SecondOrderSectionss
 #
 
-immutable Biquad{T} <: Filter
+immutable Biquad{T} <: FilterCoefficients
     b0::T
     b1::T
     b2::T
@@ -110,7 +110,7 @@ end
 # Second-order sections (array of biquads)
 #
 
-immutable SecondOrderSections{T,G} <: Filter
+immutable SecondOrderSections{T,G} <: FilterCoefficients
     biquads::Vector{Biquad{T}}
     g::G
 end
@@ -244,4 +244,4 @@ function Base.convert{Z,P}(::Type{SecondOrderSections}, f::ZeroPoleGain{Z,P})
     SecondOrderSections(biquads, f.k)
 end
 
-Base.convert(::Type{SecondOrderSections}, f::Filter) = convert(SecondOrderSections, convert(ZeroPoleGain, f))
+Base.convert(::Type{SecondOrderSections}, f::FilterCoefficients) = convert(SecondOrderSections, convert(ZeroPoleGain, f))