fdhelpstr.m

matlabDigitalSigalProcess内有文件若干

'You can also change Rs by dragging the stopband specification line up and '
'down in the main axes.'
};

case {'sb3:fdremez:min:4','sb3:fdfirls:min:4','sb3:fdkaiser:min:4','sb3:fdbutter:min:4','sb3:fdcheby1:min:4','sb3:fdcheby2:min:4','sb3:fdellip:min:4'}
str{1,1} = 'Rs';
str{1,2} = {
'This is the desired stopband attenuation Rs, in decibels.  Enter the minimum '
'amount of attenuation you desire in the stopband.'
' '
'The maximum value of the filter''s magnitude response (in dB) will not '
'exceed -Rs across the entire stopband, except in some cases with Equiripple '
'and Kaiser Window FIR designs.  The measurement "Actual Rs" displays the '
'attenuation that the filter actually achieves for these designs.'
' '
'You can also change Rs by dragging the stopband specification line up and '
'down in the main axes.'
};

case {'sb3:fdremez:set:1','sb3:fdremez:set:2','sb3:fdremez:set:3','sb3:fdremez:set:4'}
str{1,1} = 'Weight';
str{1,2} = {
'Stopband Weight'
' '
'Enter a positive real number here and hit enter to change the stopband '
'weight for the Remez algorithm.  '
' '
'Use the stopband  weight and passband weight to minimize the error more or '
'less in one band relative to the other, according to the formula:'
' '
' (max. error in passband)*(passband weight) = '
'                  (max. error in stopband)*(stopband weight)'
' '
'For example, make this number larger to lower "Actual Rs" at the expense '
'of increasing "Actual Rp".'
' '
'You can also change the ratio of the passband and stopband weights by '
'dragging the passband or stopband specifications lines up and down in the '
'main axes.  This will set the weights to approximately obtain the amount of '
'ripple Rp or Rs of the line you are dragging.'
};

case {'sb3:fdfirls:set:1','sb3:fdfirls:set:2','sb3:fdfirls:set:3','sb3:fdfirls:set:4'}
str{1,1} = 'Weight';
str{1,2} = {
'Stopband Weight'
' '
'Enter a positive real number here and hit enter to change the stopband '
'weight for the least squares design algorithm.'
' '
'Use the passband weight and stopband weight to minimize the error more or '
'less in one band relative to the other.  The larger the weight in a band, '
'the smaller the error (and ripple) will be in that band.  For example, make '
'this number larger to lower "Actual Rs" at the expense of increasing '
'"Actual Rp".'
' '
'You can also change the ratio of the passband and stopband weights by '
'dragging the passband or stopband specifications lines up and down in the '
'main axes.  This will set the weights to approximately obtain the amount of '
'ripple Rp or Rs of the line you are dragging.   However, since there is no '
'exact formula for the weights for a given Rp and Rs, the actual Rp and Rs '
'after dragging the bands may be different.'
};

case {'sb3:fdcheby1:set:1','sb3:fdellip:set:1','sb3:fdcheby1:set:2','sb3:fdellip:set:2','sb3:fdcheby1:set:3','sb3:fdellip:set:3','sb3:fdcheby1:set:4','sb3:fdellip:set:4'}
str{1,1} = 'Rs';
str{1,2} = {
'This is the desired stopband attenuation Rs, in decibels.  Enter the minimum '
'amount of attenuation you desire in the stopband.'
' '
'The maximum value of the filter''s magnitude response (in dB) will not '
'exceed -Rs across the entire stopband, except in some cases with Equiripple '
'and Kaiser Window FIR designs.  The measurement "Actual Rs" displays the '
'attenuation that the filter actually achieves for these designs.'
' '
'You can also change Rs by dragging the stopband specification line up and '
'down in the main axes.'
' '
' '
};

case {'pbm1:fdremez:min:1','pbm1:fdremez:min:2','pbm1:fdremez:min:3','pbm1:fdremez:min:4','pbm1:fdremez:set:1','pbm1:fdremez:set:2','pbm1:fdremez:set:3','pbm1:fdremez:set:4'}
str{1,1} = 'Actual Rp';
str{1,2} = {
'Actual Passband Ripple'
' '
'This is the actual passband ripple Rp, in decibels, of the designed '
'filter.  '
};

case {'pbm1:fdfirls:min:1','pbm1:fdfirls:min:2','pbm1:fdfirls:min:3','pbm1:fdfirls:min:4','pbm1:fdfirls:set:1','pbm1:fdfirls:set:2','pbm1:fdfirls:set:3','pbm1:fdfirls:set:4'}
str{1,1} = 'Actual Rp';
str{1,2} = {
'Actual Passband Ripple'
' '
'This is the actual passband ripple Rp, in decibels, of the designed '
'filter.  '
};

case {'pbm1:fdkaiser:min:1','pbm1:fdkaiser:min:2'}
str{1,1} = 'Fc';
str{1,2} = {
'Cut-off frequency Fc'
' '
'This is the frequency half way between Fp and Fs, used to define the ideal '
'"brickwall" filter which defines the filter coefficients prior to applying '
'the Kaiser window.'
};

case {'pbm1:fdkaiser:min:3','pbm1:fdkaiser:min:4'}
str{1,1} = 'Fc1';
str{1,2} = {
'Lower cut-off frequency Fc1'
' '
'This is the frequency half way between Fp1 and Fs1, used together with Fc2 '
'to define the ideal "brickwall" filter which defines the filter '
'coefficients prior to applying the Kaiser window..'
};

case {'pbm1:fdbutter:min:1','pbm1:fdbutter:min:2','pbm1:fdbutter:min:3','pbm1:fdbutter:min:4'}
str{1,1} = 'Actual Rp';
str{1,2} = {
'Actual Passband Ripple'
' '
'This is the actual passband ripple Rp, in decibels, of the designed filter.  '
'This number is often smaller than the desired passband ripple Rp under '
'"Specifications" because Butterworth filters meet the stopband '
'specification exactly and exceed the passband specification.'
};

case {'pbm1:fdkaiser:set:1','pbm1:fdkaiser:set:2','pbm1:fdbutter:set:1','pbm1:fdbutter:set:2','pbm1:fdcheby2:set:1','pbm1:fdcheby2:set:2'}
str{1,1} = 'Fp';
str{1,2} = {
'Passband Edge Frequency Fp (Interactive)'
' '
'This is the passband edge frequency Fp.  Enter a frequency here and Rp '
'changes to reflect how much ripple is in the passband given the passband '
'edge which you entered.'
' '
'Fp and Rp define an "interactive passband measurement" which allows you to '
'ask questions such as, "if the lower passband edge is at 50 Hz (for '
'instance), what is the ripple Rp in the passband?".  If you change either '
'Fp or Rp, the other measurement changes to reflect the passband given the '
'parameter you entered.  You can also drag the passband measurement line in '
'the main axes area, either up and down to change Rp, or back and forth to '
'change Fp.'
};

case {'pbm1:fdkaiser:set:3','pbm1:fdkaiser:set:4','pbm1:fdbutter:set:3','pbm1:fdbutter:set:4','pbm1:fdcheby2:set:3','pbm1:fdcheby2:set:4'}
str{1,1} = 'Fp1';
str{1,2} = {
'Lower Passband Edge Frequency Fp1 (Interactive)'
' '
'This is the lower passband edge frequency Fp1.  Enter a frequency here and '
'Rp changes to reflect how much ripple is in the passband at the passband '
'edge which you entered.  Fp2 also changes to reflect how far the passband '
'extends given the new ripple Rp.'
' '
'Fp1, Fp2, and Rp define an "interactive passband measurement" which allows '
'you to ask questions such as, "if the lower passband edge is at 50 Hz (for '
'instance), what is the ripple Rp in the passband?".  If you change any of'
'Fp1, Fp2 or Rp, the other two measurements change to reflect the passband '
'given the parameter you entered.  You can also drag the passband measurement'
'line in the main axes area, either up and down to change Rp, or back and '
'forth to change Fp1 or Fp2.'
};

case {'pbm2:fdremez:min:1','pbm2:fdremez:min:2','pbm2:fdremez:min:3','pbm2:fdremez:min:4'}
str{1,1} = 'Weight';
str{1,2} = {
'Passband Weight'
' '
'This positive real number is the passband weight for the Remez algorithm.'
' '
'The passband weight and stopband weight minimize the error more or '
'less in one band relative to the other, according to the formula:'
' '
' (max. error in passband)*(passband weight) = '
'                  (max. error in stopband)*(stopband weight)'
' '
'For minimum order filters, the passband and stopband weights are determined '
'by the desired Rp and Rs specifications.  Rp and Rs are converted to linear '
'scale to determine the quantities delta_p and delta_s, the desired maximum '
'error versus the ideal passband and stopband responses, respectively:'
'    delta_p = (10^(Rp/20)-1)/(10^(Rp/20)+1)'
'    delta_s = 10^(-Rs/20)'
' '
'The passband and stopband weight are then determined by'
'    passband weight = 1/delta_p * max([delta_p, delta_s])'
'    stopband weight = 1/delta_s * max([delta_p, delta_s])'
};

case {'pbm2:fdkaiser:min:3','pbm2:fdkaiser:min:4'}
str{1,1} = 'Fc2';
str{1,2} = {
'Upper cut-off frequency Fc2'
' '
'This is the frequency half way between Fp2 and Fs2, used together with Fc1 '
'to define the ideal "brickwall" filter which defines the filter '
'coefficients prior to applying the Kaiser window..'
};

case {'pbm2:fdkaiser:set:3','pbm2:fdkaiser:set:4','pbm2:fdbutter:set:3','pbm2:fdbutter:set:4','pbm2:fdcheby2:set:3','pbm2:fdcheby2:set:4'}
str{1,1} = 'Fp2';
str{1,2} = {
'Lower Passband Edge Frequency Fp2 (Interactive)'
' '
'This is the upper passband edge frequency Fp2.  Enter a frequency here and '
'Rp changes to reflect how much ripple is in the passband at the passband '
'edge which you entered.  Fp1 also changes to reflect how far the passband '
'extends given the new ripple Rp.'
' '
'Fp1, Fp2, and Rp define an "interactive passband measurement" which allows '
'you to ask questions such as, "if the upper passband edge is at 50 Hz (for '
'instance), what is the ripple Rp in the passband?".  If you change any of'
'Fp1, Fp2 or Rp, the other two measurements change to reflect the passband '
'given the parameter you entered.  You can also drag the passband measurement'
'line in the main axes area, either up and down to change Rp, or back and '
'forth to change Fp1 or Fp2.'
' '
};

case {'pbm3:fdkaiser:min:1','pbm3:fdkaiser:min:2','pbm3:fdkaiser:min:3','pbm3:fdkaiser:min:4'}
str{1,1} = 'Beta';
str{1,2} = {
'Beta of Kaiser Window'
' '
'This is the Beta parameter chosen in attempt to meet the desired pass and '
'stopband specifications.  See the function KAISERORD for more details.'
};

case {'pbm3:fdkaiser:set:1','pbm3:fdkaiser:set:2','pbm3:fdbutter:set:1','pbm3:fdbutter:set:2','pbm3:fdcheby2:set:1','pbm3:fdcheby2:set:2'}
str{1,1} = 'Rp';
str{1,2} = {
'Passband Ripple Rp (Interactive)'
' '
'This is the passband ripple Rp, in decibels.  Enter a number here and Fp '
'changes to reflect how far the passband extends given the new ripple that '
'you have entered.'
' '
'Fp and Rp define an "interactive passband measurement" which allows you to '
'ask questions such as, "if the upper passband edge is at 50 Hz (for '
'instance), what is the ripple Rp in the passband?".  If you change either '
'Fp or Rp, the other measurement changes to reflect the passband given the '
'parameter you entered.  You can also drag the passband measurement line in '
'the main axes area, either up and down to change Rp, or back and forth to '
'change Fp.'
};

case {'pbm3:fdkaiser:set:3','pbm3:fdkaiser:set:4','pbm3:fdbutter:set:3','pbm3:fdbutter:set:4','pbm3:fdcheby2:set:3','pbm3:fdcheby2:set:4'}
str{1,1} = 'Rp';
str{1,2} = {
'Passband Ripple Rp (Interactive)'
' '
'This is the passband ripple Rp, in decibels.  Enter a number here and Fp1 '
'and Fp2 change to reflect how far the passband extends given the new ripple '
'that you have entered.'
' '
'Fp1, Fp2, and Rp define an "interactive passband measurement" which allows '
'you to ask questions such as, "if the upper passband edge is at 50 Hz (for '
'instance), what is the ripple Rp in the passband?".  If you change any of'
'Fp1, Fp2 or Rp, the other two measurements change to reflect the passband '
'given the parameter you entered.  You can also drag the passband measurement'
'line in the main axes area, either up and down to change Rp, or back and '
'forth to change Fp1 or Fp2.'
' '
' '
' '
};

case {'sbm1:fdremez:min:1','sbm1:fdremez:min:2','sbm1:fdremez:min:3','sbm1:fdremez:min:4','sbm1:fdremez:set:1','sbm1:fdremez:set:2','sbm1:fdremez:set:3','sbm1:fdremez:set:4'}
str{1,1} = 'Actual Rs';
str{1,2} = {
'Actual Stopband Attenuation'
' '
'This is the actual stopband attenuation Rs, in decibels, of the designed '
'filter.  '
};

case {'sbm1:fdfirls:min:1','sbm1:fdfirls:min:2','sbm1:fdfirls:min:3','sbm1:fdfirls:min:4','sbm1:fdfirls:set:1','sbm1:fdfirls:set:2','sbm1:fdfirls:set:3','sbm1:fdfirls:set:4'}
str{1,1} = 'Actual Rs';
str{1,2} = {
'Actual Stopband Attenuation'
' '
'This is the actual stopband attenuation Rs, in decibels, of the designed '
'filter.  '
};

case {'sbm1:fdkaiser:min:1','sbm1:fdkaiser:min:2','sbm1:fdkaiser:min:3','sbm1:fdkaiser:min:4'}
str{1,1} = 'Actual Rp';
str{1,2} = {
'Actual Passband Ripple'
' '
'This is the actual passband ripple Rp, in decibels, of the designed '
'filter.  '
};

case {'sbm1:fdbutter:min:1','sbm1:fdbutter:min:2'}
str{1,1} = 'F3dB';
str{1,2} = {
'3 dB Frequency F3dB'
' '
'This is the frequency where the Butterworth filter''s magnitude response '
'equals 1/sqrt(2), or approximately -3 decibels.  '
' '
'For typical filters (in which Rp < 3 and Rs > 3), this frequency will be '
'between Fp and Fs.'
'  For lowpass: Fp < F3dB < Fs'
'  For highpass: Fs < F3dB < Fp                '
};

case 'sbm1:fdbutter:min:3'
str{1,1} = 'F3dB 1';
str{1,2} = {
'Lower 3 dB Frequency F3dB 1'
' '
'This is the lower frequency where the Butterworth filter''s magnitude '
'response equals 1/sqrt(2), or approximately -3 decibels.'
' '
'For typical filters (in which Rp < 3 and Rs > 3), this frequency will be '
'between Fp1 and Fs1, i.e.'
'  Fs1 < F3dB 1 < Fp1 < Fp2 < F3dB 2 < Fs2'
};

case 'sbm1:fdbutter:min:4'