bencholmes

FILENAME="$1"

# https://stackoverflow.com/questions/1672580/get-number-of-pages-in-a-pdf-using-a-cmd-batch-file
# Uses pdfinfo to find general information, focusing on the number of pages from which only the number is extracted.
NPAGES=$(pdfinfo "$FILENAME" | grep Pages | sed 's/[^0-9]*//')

# https://root42.blogspot.com/2012/10/counting-color-pages-in-pdf-files.html
# Uses ghostscript to measure any deviation from black in the ink colour used on pages.
GHOSTOUT=$(gs -o - -sDEVICE=inkcov $FILENAME | grep -v "^ 0.00000  0.00000  0.00000" | grep "^ " | wc -l)

bencholmes

%%% Low Pass Circuit
% A computable RC circuit model using a recurrence relation derived from
% MNA, through to a transfer function which is then discretised using the
% symbolic math toolbox.

% Author: Ben Holmes
% Date: 2019/01/01
% License: GPL v3

clear;

bencholmes

Calculate full frame to cropped equivalent. First order approximations only. Designed as described by <a href="https://northrup.photo/gear-basics/camera-body-features/sensor-size-crop-factor/">Chelsea and Tony Northrup</a>.

<form name="cropCalculator" action="" method="get">
	<table>
    	<tr>
        	<td>Crop factor:</td>
            <td><input type="text" name="cropFactor" value="1.53"></td>
        </tr>
        <tr>
        	<td>Direction:</td>

bencholmes

function X = forceFFTSymmetry(X)
% forceFFTSymmetry  A function to force conjugate symmetry on an FFT such that when an
% IFFT is performed the result is a real signal.

% The function has been written to replace MATLAB's ifft(X,'symmetric'), as this function
% is not compatible with MATLAB Coder.
  
% Licensed under Creative Commons Zero (CC0) so use freely.

XStartFlipped = fliplr(X(2:floor(end/2)));

bencholmes

fileName=$(basename $1)
directory=$(dirname $1)
gs \
 -sOutputFile="$directory/${fileName%.*}-grayscale.pdf" \
 -sDEVICE=pdfwrite \
 -sColorConversionStrategy=Gray \
 -dProcessColorModel=/DeviceGray \
 -dCompatibilityLevel=1.4 \
 -dAutoRotatePages=/None \
 -dNOPAUSE \

bencholmes

function [Xmag, Xarg] = fftdBV(x)
%FFTDBV Returns the FFT of a voltage signal (in volts) with the amplitude response units dBV.

% Number of samples
N = length(x);

% Scaling factor is sqrt(2) except for at DC when it is 1.
k  = [1, ones(1,N-1)*sqrt(2)];

% Calculate the scaled DFT.

bencholmes

function [Ac,Bc,Cc,Dc] = cascadeSSM(A,B,C,D)
% CASCADESSM    A function to cascade linear state-space matrices for the
% purpose of cascading filters etc.
%
% Author:  Ben Holmes
% Date:    2018/05/20
% License: GPL V3
%
% This function is derived from the answer
% https://math.stackexchange.com/questions/2201067/cascade-of-state-space-models-for-linear-systems

bencholmes

function string = engFormat(value, type)
%ENGFORMAT a function to take a passive electronic component value and
% return a string with the properly formatted suffix.

aVal = abs(value);
nn = 0;

if strcmp(type,'R')
    type = char(937);
end

bencholmes

function [transferFunction] = circuitShelf(isHighShelf,R,C,f)
%%% CircuitShelf: A circuit informed shelf filter written as a continuous
%%% time transfer function.
% Author:   Ben Holmes
% Date:     2017/12/16
% License:  GPL v3

% Arguments:
%   - isHighShelf:  Boolean variable to switch between highpass and lowpass
%   - R:            2x1 vector of resistor values

bencholmes

function [I, J] = bjt(v, Is, N, Bf, Br)
% BJT: a general model for the currents through a BJT and their
% derivatives.
% Ben Holmes, 2017/11/28, GPL 3.0
% Arguments:
%   - v:    [vce; vbe], collector-emitter voltage and base-emitter voltage.
%   - Is:   saturation current
%   - N:    ideality factor
%   - Bf:   forward current gain
%   - Br:   reverse current gain