fdhelpstr.m

matlabDigitalSigalProcess内有文件若干

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.'
'  Fp1 < F3dB 1 < Fs1 < Fs2 < F3dB 2 < Fp2'
' '
};

case {'sbm1:fdcheby1:min:1','sbm1:fdcheby1:min:2','sbm1:fdcheby2:min:1','sbm1:fdcheby2:min:2','sbm1:fdellip:min:1','sbm1:fdellip:min:2'}
str{1,1} = 'Actual Fs';
str{1,2} = {
'Actual Stopband Edge Fs'
' '
'For this type of filter, the actual stopband is usually wider than the '
'desired stopband as specified by Fs under "Specifications".  This '
'measurement records the actual stopband edge Fs for this filter.'
};

case {'sbm1:fdcheby1:min:3','sbm1:fdcheby1:min:4','sbm1:fdcheby2:min:3','sbm1:fdcheby2:min:4','sbm1:fdellip:min:3','sbm1:fdellip:min:4'}
str{1,1} = 'Actual Fs1';
str{1,2} = {
'Actual Lower Stopband Edge Fs1'
' '
'For this type of filter, the actual stopband is usually wider than the '
'desired stopband as specified by Fs1 and Fs2 under "Specifications".  This '
'measurement records the actual lower stopband edge Fs1 for this filter.'
};

case {'sbm2:fdellip:set:1','sbm2:fdellip:set:2'}
str{1,1} = 'Fs';
str{1,2} = {
'Stopband Edge Fs'
' '
'For Elliptic filters, you specify the passband edge Fp, and the transition '
'width is minimized for a given filter order.  This measurement records the '
'actual stopband edge Fs for this filter.'
};

case {'sbm2:fdellip:set:3','sbm2:fdellip:set:4'}
str{1,1} = 'Fs1';
str{1,2} = {
'Lower Stopband Edge Fs1'
' '
'For Elliptic filters, you specify the passband edges Fp1 and Fp2, and the '
'transition width is minimized for a given filter order.  This measurement '
'records the actual lower stopband edge Fs1 for this filter.'
};

case {'sbm1:fdkaiser:set:1','sbm1:fdkaiser:set:2','sbm1:fdbutter:set:1','sbm1:fdbutter:set:2','sbm1:fdcheby1:set:1','sbm1:fdcheby1:set:2'}
str{1,1} = 'Fs';
str{1,2} = {
'Stopband Edge Frequency Fs (Interactive)'
' '
'This is the stopband edge frequency Fs.  Enter a frequency here and Rs '
'changes to reflect how much attenuation is achieved in the stopband given '
'the stopband edge which you entered.'
' '
'Fs and Rs define an "interactive stopband measurement" which allows you to '
'ask questions such as, "if the stopband edge is at 50 Hz (for instance), '
'what is the attenuation Rs in the stopband?".  If you change either Fs or '
'Rs, the other stopband measurement changes to reflect the stopband given '
'the parameter you entered.  You can also drag the stopband measurement line '
'in the main axes area, either up and down to change Rs, or back and forth '
'to change Fs.'
};

case {'sbm1:fdkaiser:set:3','sbm1:fdkaiser:set:4','sbm1:fdbutter:set:4','sbm1:fdbutter:set:4','sbm1:fdcheby1:set:3','sbm1:fdcheby1:set:4'}
str{1,1} = 'Fs1';
str{1,2} = {
'Lower Stopband Edge Frequency Fs1 (Interactive)'
' '
'This is the lower stopband edge frequency Fs1.  Enter a frequency here and Rs '
'changes to reflect how much attenuation is achieved in the stopband given '
'the stopband edge which you entered.  Fs2 also changes to reflect how far '
'the passband extends given the new attenuation Rs.'
' '
'Fs1, Fs2 and Rs define an "interactive stopband measurement" which allows '
'you to ask questions such as, "if the lower stopband edge is at 50 Hz (for '
'instance), what is the attenuation Rs in the stopband?".  If you change any '
'of Fs1, Fs2 or Rs, the other two stopband measurements change to reflect '
'the stopband given the parameter you entered.  You can also drag the '
'stopband measurement line in the main axes area, either up and down to '
'change Rs, or back and forth to change Fs1 or Fs2.'
' '
};

case {'sbm2:fdremez:min:1','sbm2:fdremez:min:2','sbm2:fdremez:min:3','sbm2:fdremez:min:4'}
str{1,1} = 'Weight';
str{1,2} = {
'Stopband Weight'
' '
'This positive real number is the stopband 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 {'sbm2:fdkaiser:min:1','sbm2:fdkaiser:min:2','sbm2:fdkaiser:min:3','sbm2:fdkaiser:min:4'}
str{1,1} = 'Actual Rs';
str{1,2} = {
'Actual Stopband Attenuation'
' '
'This is the actual stopband attenution Rs, in decibels, of the designed '
'filter.  '
};

case 'sbm2:fdbutter:min:3'
str{1,1} = 'F3dB 2';
str{1,2} = {
'Upper 3 dB Frequency F3dB 2'
' '
'This is the upper 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 Fp2 and Fs2, i.e.'
'  Fs1 < F3dB 1 < Fp1 < Fp2 < F3dB 2 < Fs2'
};

case 'sbm2:fdbutter:min:4'
str{1,1} = 'F3dB 2';
str{1,2} = {
'Upper 3 dB Frequency F3dB 2'
' '
'This is the upper 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 Fp2 and Fs2, i.e.'
'  Fp1 < F3dB 1 < Fs1 < Fs2 < F3dB 2 < Fp2'
};

case {'sbm2:fdcheby1:min:3','sbm2:fdcheby1:min:4','sbm2:fdcheby2:min:3','sbm2:fdcheby2:min:4','sbm2:fdellip:min:3','sbm2:fdellip:min:4'}
str{1,1} = 'Actual Fs2';
str{1,2} = {
'Actual Upper Stopband Edge Fs2'
' '
'For this type of filter, the actual stopband is usually wider than the '
'desired stopband as specified by Fs1 and Fs2 under "Specifications".  This '
'measurement records the actual upper stopband edge Fs2 for this filter.'
};

case {'sbm2:fdellip:set:3','sbm2:fdellip:set:4'}
str{1,1} = 'Fs2';
str{1,2} = {
'Upper Stopband Edge Fs2'
' '
'For Elliptic filters, you specify the passband edges Fp1 and Fp2, and the '
'transition width is minimized for a given filter order.'
' '
'This measurement records the upper stopband edge Fs2 for this filter.'
' '
};

case {'sbm2:fdkaiser:set:3','sbm2:fdkaiser:set:4','sbm2:fdbutter:set:4','sbm2:fdbutter:set:4','sbm2:fdcheby1:set:3','sbm2:fdcheby1:set:4'}
str{1,1} = 'Fs2';
str{1,2} = {
'Upper Stopband Edge Frequency Fs2 (Interactive)'
' '
'This is the upper stopband edge frequency Fs2.  Enter a frequency here and '
'Rs changes to reflect how much attenuation is achieved in the stopband '
'given the stopband edge which you entered.  Fs1 also changes to reflect how '
'far the passband extends given the new attenuation Rs.'
' '
'Fs1, Fs2 and Rs define an "interactive stopband measurement" which allows '
'you to ask questions such as, "if the lower stopband edge is at 50 Hz (for '
'instance), what is the attenuation Rs in the stopband?".  If you change any '
'of Fs1, Fs2 or Rs, the other two stopband measurements change to reflect '
'the stopband given the parameter you entered.  You can also drag the '
'stopband measurement line in the main axes area, either up and down to '
'change Rs, or back and forth to change Fs1 or Fs2.'
' '
};

case {'sbm3:fdkaiser:set:1','sbm3:fdkaiser:set:2','sbm3:fdbutter:set:1','sbm3:fdbutter:set:2','sbm3:fdcheby1:set:1','sbm3:fdcheby1:set:2'}
str{1,1} = 'Rs';
str{1,2} = {
'Stopband Attenuation Rs (Interactive)'
' '
'This is the stopband attenuation Rs, in decibels.  Enter a number here and '
'Fs changes to reflect how far the stopband extends given the new '
'attenuation that you have entered.'
' '
'Fs and Rs define an "interactive stopband measurement" which allows you to '
'ask questions such as, "if the stopband edge is at 50 Hz (for instance), '
'what is the attenuation Rs in the stopband?".  If you change either Fs or '
'Rs, the other measurement changes to reflect the stopband given the '
'parameter you entered.  You can also drag the stopband measurement line in '
'the main axes area, either up and down to change Rs, or back and forth to '
'change Fs.'
};

case {'sbm3:fdkaiser:set:3','sbm3:fdkaiser:set:4','sbm3:fdbutter:set:3','sbm3:fdbutter:set:4','sbm3:fdcheby1:set:3','sbm3:fdcheby1:set:4'}
str{1,1} = 'Rs';
str{1,2} = {
'Stopband Attenuation Rs (Interactive)'
' '
'This is the stopband attenuation Rs, in decibels.  Enter a number here and '
'Fs1 and Fs2 change to reflect how far the stopband extends given the new '
'attenuation that you have entered.'
' '
'Fs1, Fs2, and Rs define an "interactive stopband measurement" which allows '
'you to ask questions such as, "if the upper stopband edge is at 50 Hz (for '
'instance), what is the attenuation Rs in the stopband?".  If you change any of'
'Fs1, Fs2 or Rs, the other two measurements change to reflect the stopband '
'given the parameter you entered.  You can also drag the stopband measurement'
'line in the main axes area, either up and down to change Rs, or back and '
'forth to change Fs1 or Fs2.'
' '
' '
};

case 'ax'
str{1,1} = 'MAIN AXES';
str{1,2} = {
'Main Axes'
' '
'The main axes consists of a display of the current filter''s frequency '
'response, and other lines which are used to either manipulate or measure '
'the filter.  When moving the mouse over these lines, you will see the mouse '
'pointer change to indicate you can perform some action by clicking and '
'dragging the line, usually up and down or back and forth.'
' '
'GREEN LINES are specification lines, and dragging them causes the filter'
'to be redesigned.  If "AutoDesign" is checked, the filter will redesign'
'as you drag the mouse - this is recommended only for the fastest machines.'
'If "AutoDesign" is not checked, the filter will be designed when you'
'release the mouse button (after you are done dragging the line to its'
'desired location).  The Filter Designer will do its best to meet the '
'specifications, but in the case of REMEZ and KAISER, the response will'
'sometimes exceed the green lines.'
' '
'RED LINES are measurement lines, and dragging them does not cause the'
'filter to be redesigned.  As you drag these lines, some measurements on'
'the right will change to reflect the changed position of the line.'
' '
'You can also drag the FREQUENCY RESPONSE LINE.  In this case, when you'
'are zoomed-in, dragging this line allows you to see other parts of the'
'response which are off the screen.  When you release the mouse button, the'
'only thing that changes are the axes limits.'
' '
'To get help on a line (to see what it represents and how to drag it), click the '
'help button and then click on the line.'
' '
};

case 'response'
str{1,1} = 'Response';
str{1,2} = {
'Frequency Response'
' '
'This line plots the magnitude of the filter''s frequency response, in '
'decibels (20*log10(magnitude)). '
' '
'When you are zoomed-in, dragging this line allows you to see other parts of '
'the response which are off the screen.  When you release the mouse button, '
'the only thing that changes are the axes limits.'
' '
'The resolution of this line is controlled by the Nfft parameter, which you '
'can change under the "Filter Designer" category of the Preferences option '
'of the SPTool.  The line plots the magnitude at Nfft evenly spaced '
'frequencies between 0 and Fsamp/2.'
' '
};

case 'overlayline'
str{1,1} = 'Overlaid Spectrum';
str{1,2} = {
'Overlaid Spectrum Plot'
' '
'This line corresponds to a spectrum plot.  To change or remove this line,'
'click the "Overlay Spectrum" button.'
' '
'This feature is useful if you would like to design a filter to'
'pass or stop a certain range of frequencies designated by the'
'frequency content of a signal.'
' '
'The spectrum and filter may have different sampling frequencies, in which '
'case the spectrum''s frequency extent will not match the filter''s.'
' '
};

case {'passband:min','passband:fdcheby1:set','passband:fdellip:set'}
str{1,1} = 'Passband Line';
str{1,2} = {
'Passband Specifications Line'
' '
'This line consists of upper and lower horizontal segments which denote the '
'maximum and minimum desired values for the frequency response across the '
'passband.'
' '
'As you move the mouse over these line segments, the cursor changes to '
'indicate that you can drag the line, either back and forth, or up and down, '
'depending on if you are over the end of a line segment, or over the center '
'of the line segment.  '
' '
'BACK AND FORTH DRAGGING'
'When the cursor indicates two arrows facing left and right, you can click '
'and drag the band edge back and forth.  As you do so, the line follows the '
'mouse and the associated frequency changes under "Specifications".  When '
'you let go of the mouse button, the filter is redesigned.'
' '
'UP AND DOWN DRAGGING'
'When the cursor indicates two arrows facing up and down, you can click and '
'drag the passband ripple up and down.  As you do so, the line