PROJECT_FUNCTION_LIBRARY.txt

Library of M-files desiged for main programs: Phase{1,2,3,4,5} and for future
work in filter design


FUNCTION: cardinalSinShifted

CALL: hn = cardinalSinShifted(M, wc, Ts)

Evaluates the sampled version of a continous sinc in M 
points with the sampling period Ts

%-----------------------------------------------------------------------------%

FUNCTION: changePhaseToLinear

CALL: [H_new, b, a] = changePhaseToLinear(b, a)

Takes in filter coefficients for any given filter and returns
the coefficients of a filter with linear pahse and the same
spectruum

%-----------------------------------------------------------------------------%

FUNCTION: checkError

CALL: check = checkError(deltaP, deltaP_max, deltaS, deltaS_max)

Checks if deltaP < deltaP_max and deltaS < deltaS_max, and returns
1 if the conditions hold

%-----------------------------------------------------------------------------%

FUNCTION: checkType

CALL: check = checkType(type, indx)

Checks if a given window it's in one of the specified sets, indx must be
a vector with values in range 1 to 9. Returns 1 if the window given by
the parameter type it's one from the values at indx

%-----------------------------------------------------------------------------%

FUNCTION: filterDesign

CALL: [b, a, filterOrder, deltaP_real, deltaS_real, error, found] =....
                filterDesign(Fp, Fs, deltaP, deltaS, Ts, Wn, wn_param, M, type)

Returns the impulse response of the best filter with passband frequency Fp
and stopband frequency Fs, with sampling period Ts with order less than M
and which respects the passband deltaP and stopband deltaS constraints for
a given window

%-----------------------------------------------------------------------------%

FUNCTION: FIR

CALL: [b, a] = FIR(order, wc, Ts, window, type)

The functions returns a FIR filter of type type and of order order and cutoff
frequency wc with sampling period Ts using the window given by the vector window


%-----------------------------------------------------------------------------%

FUNCTION: getWindow

CALL: Wn = getWindow(Wn, order, wn_param)

Returns a window of type Wn of length order
DEFAULT: hanning window of length 16

%-----------------------------------------------------------------------------%

FUNCTION: getWindowName

CALL: [w, titles] = getWindowName()

Returns the standard window names and titles for frequency response


%-----------------------------------------------------------------------------%

FUNCTION: lanczos

CALL: h = lanczos(M, L)

Returns the values of a lanczos window of length M using the extra
parameter L 

%-----------------------------------------------------------------------------%

FUNCTION: plotFilterDesign

CALL: [deltaP_real, deltaS_real, error] =....
   plotFilterDesign(Fp, Fs, deltaP, deltaS, Ts, Wn, wn_param, M, plots)

Plots the impulse response of the best filter with passband frequency Fp
and stopband frequency Fs, with sampling period Ts with order less than M
and which respects the passband deltaP and stopband deltaS constraints for
a given window

%-----------------------------------------------------------------------------%

FUNCTION plotGain

CALL: [] = plotGain(H, omeg, titleNormalScale)

Plots the frequency response of a filter on the scale omeg with title
given by titleNormalScale

%-----------------------------------------------------------------------------%

FUNCTION plotGainDB

CALL: [] = plotGainDB(H, omeg, titleDBScale)

Plots the frequency response in dB of a filter on the scale omeg with title
given by titleDBScale

%-----------------------------------------------------------------------------%

FUNCTION plotPhase

CALL: [] = plotPhase(H, omeg, titlePhase)

Plots the frequency response phase of a filter on the scale omeg with title
given by titlePhase

%-----------------------------------------------------------------------------%

FUNCTION: plotWindowFIRResponse

CALL: [] = plotWindowFIRResponse(w, titles, order, wc, Ts, wn_param)

Plots the frequency response of the specified windows, with cutoff
frequency wc, samplit period Ts and using the parameters in wn_param for
the windows.
SUPPORTS ONLY LOW-PASS FILTER AT THE MOMENT !

%-----------------------------------------------------------------------------%

FUNCTION: rankFilters

CALL: [rankingFilters, tableRank, error] =....
   rankFilters(Fp, Fs, deltaP, deltaS, Ts, Wn, wn_param, M, type)

Returns the best filters with passband frequency Fp and stopband frequency Fs,
with sampling period Ts with order less than M and which respects the passband
deltaP and stopband deltaS constraints for a all 9 windows 

%-----------------------------------------------------------------------------%

FUNCTION: returnMaxError

CALL: [deltaP_max, deltaS_max] = returnMaxError(H, w, wp, ws, type)

Returns the maximum passband error and the maximum stopband error
for a given filter

%-----------------------------------------------------------------------------%

FUNCTION: setDefaultParamsForAllWindows

CALL: wn_param = setDefaultParamsForAllWindows(Wn)

Returns the default parameters for all windows


%-----------------------------------------------------------------------------%

FUNCTION: setParamFor

CALL: wn_param = setParamFor(Wn)
 
Returns the default parameters for the given window

%-----------------------------------------------------------------------------%

FUNCTION: truncateCellArray

CALL: truncatedCellArray = truncateCellArray(cellArray, new_size)
 
The functions truncate the input cell array to the new_size, if no new
    size is given the output cell array has the same length as the input