hi.... i'm currently working on Analog Devices Dsp processor ADAU 1701.. Sigma studio is the software we are now on,in that i have some queries in the way they calculate filter coefficient. - main specification i needed to design a filter 1)Type[LPF,HPF, etc] 2)frequency 3)Q 4)Gain eg: I want a 2nd order LPF with Frequency= 1000 Q=0.5 Gain=1 The given below derivation is the one which i got from sigma studio help window. ->ω0 = 2*pi*f0/Fs ->gainLinear = 10^(gain/20) ->Lowpass ->Transfer Function ->H(s)=1/(s^2+(s/Q)+1) ->Coefficients ->alpha = sin(ω0)/(2*Q) ->a0 = 1 + alpha ->a1 = -2*cos(ω0) ->a2 = 1 - alpha ->b0 = (1 - cos(ω0)) * gainLinear / 2 ->b1 = 1 - cos(ω0) * gainLinear ->b2 = (1 - cos(ω0)) * gainLinear / 2 After compiling we'll get coefficients a1,a2,b0,b1,b2 in hex format in CAPTURE WINDOW of software. i did manual calculation using the expression provided above and compare with that of coeffients of software, but it differs. Please help me to get detail calculation with the specification i given above. We know ω0 = 2*pi*f0/Fs -what is the value of pi(180 0r 3.14) -ω0 is the angular representation of requency i think it will be 180 -then in above value of alpha will be zero always. -it means Q doesnt have any importantce in filter design -please suggest a good book which describe in detail about filter design with regards rammya
Filter coefficient calculation In Sigma studio
Started by ●February 9, 2010
Reply by ●February 9, 20102010-02-09
rammya.tv wrote:> hi.... > i'm currently working on Analog Devices Dsp processor ADAU 1701.. > Sigma studio is the software we are now on,in that i have some queries in > the way they calculate filter coefficient. > > - main specification i needed to design a filter > 1)Type[LPF,HPF, etc] > 2)frequency > 3)Q > 4)Gain > > eg: > I want a 2nd order LPF with > Frequency= 1000 > Q=0.5 > Gain=1 > > The given below derivation is the one which i got from sigma studio help > window. > > ->ω0 = 2*pi*f0/Fs > ->gainLinear = 10^(gain/20) > > ->Lowpass > > ->Transfer Function > ->H(s)=1/(s^2+(s/Q)+1) > > ->Coefficients > ->alpha = sin(ω0)/(2*Q) > ->a0 = 1 + alpha > ->a1 = -2*cos(ω0) > ->a2 = 1 - alpha > ->b0 = (1 - cos(ω0)) * gainLinear / 2 > ->b1 = 1 - cos(ω0) * gainLinear > ->b2 = (1 - cos(ω0)) * gainLinear / 2I can't see your omega unless I switch to unicode. It seems gauche, but it is the custom here to use 'w' instead.> After compiling we'll get coefficients a1,a2,b0,b1,b2 in hex format in > CAPTURE WINDOW of software. > i did manual calculation using the expression provided above and compare > with that of coeffients of software, but it differs. > Please help me to get detail calculation with the specification i given > above. > > > We know ω0 = 2*pi*f0/Fs > -what is the value of pi(180 0r 3.14) > -ω0 is the angular representation of requency i think it will be 180 > -then in above value of alpha will be zero always. > -it means Q doesnt have any importantce in filter design > -please suggest a good book which describe in detail about filter designIt will be 180 what? All angles above are in radians. 'w' (or ω) is for radians/second. For cycles/second (Hz), it's 'f'. One cycle is 2*pi radians. That pi radians equal 180 degrees doesn't make pi (Π) equal to 180. There's no magic that can make it so. Jerry -- Engineering is the art of making what you want from things you can get. ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Reply by ●February 9, 20102010-02-09
On Feb 8, 11:36 pm, "rammya.tv" <rammya...@ymail.com> wrote:> hi.... > i'm currently working on Analog Devices Dsp processor ADAU 1701.. > Sigma studio is the software we are now on,in that i have some queries in > the way they calculate filter coefficient. > > - main specification i needed to design a filter > 1)Type[LPF,HPF, etc] > 2)frequency > 3)Q > 4)Gain > > eg: > I want a 2nd order LPF with > Frequency= 1000 > Q=0.5 > Gain=1 > > The given below derivation is the one which i got from sigma studio help > window. > > ->ω0 = 2*pi*f0/Fs > ->gainLinear = 10^(gain/20) > > ->Lowpass > > ->Transfer Function > ->H(s)=1/(s^2+(s/Q)+1) > > ->Coefficients > ->alpha = sin(ω0)/(2*Q) > ->a0 = 1 + alpha > ->a1 = -2*cos(ω0) > ->a2 = 1 - alpha > ->b0 = (1 - cos(ω0)) * gainLinear / 2 > ->b1 = 1 - cos(ω0) * gainLinear > ->b2 = (1 - cos(ω0)) * gainLinear / 2 > > After compiling we'll get coefficients a1,a2,b0,b1,b2 in hex format in > CAPTURE WINDOW of software. > i did manual calculation using the expression provided above and compare > with that of coeffients of software, but it differs. > Please help me to get detail calculation with the specification i given > above. > > We know ω0 = 2*pi*f0/Fs > -what is the value of pi(180 0r 3.14)the latter.> -ω0 is the angular representation of frequency i think it will be 180w0 is unitless but would be "radians per sample" and is always less than pi.> -then in above value of alpha will be zero always. > -it means Q doesnt have any importantce in filter designGIGO> -please suggest a good book which describe in detail about filter designit looks like you've been to the cookbook. there *is* actually sufficient detail in the "FYI" at the bottom to show how all the coefs were designed. but look for Zoelzer's book, i guess. the formulae have been used over and over and i'm confident are correct for how the parameters are defined in the cookbook. try reading it carefully and not making any funky assumptions. there are plenty of folks here who can help you. r b-j r b-j
Reply by ●February 10, 20102010-02-10
rammya.tv hi.... i'm currently working on Analog Devices Dsp processor ADAU 1701.. Sigma studio is the software we are now on,in that i have some queries in the way they calculate filter coefficient. - main specification i needed to design a filter 1)Type[LPF,HPF, etc] 2)frequency 3)Q 4)Gain eg: I want a 2nd order LPF with Frequency= 1000 Q=0.5 Gain=1 The given below derivation is the one which i got from sigma studio help window. ->w0 = 2*pi*f0/Fs ->gainLinear = 10^(gain/20) ->Lowpass ->Transfer Function ->H(s)=1/(s^2+(s/Q)+1) ->Coefficients ->alpha = sin(w0)/(2*Q) ->a0 = 1 + alpha ->a1 = -2*cos(w0) ->a2 = 1 - alpha ->b0 = (1 - cos(w0)) * gainLinear / 2 ->b1 = 1 - cos(w0) * gainLinear ->b2 = (1 - cos(w0)) * gainLinear / 2 I can't see your omega unless I switch to unicode. It seems gauche, but it is the custom here to use 'w' instead. After compiling we'll get coefficients a1,a2,b0,b1,b2 in hex format in CAPTURE WINDOW of software. i did manual calculation using the expression provided above and compare with that of coeffients of software, but it differs. Please help me to get detail calculation with the specification i given above. We know w0 = 2*pi*f0/Fs -what is the value of pi(180 0r 3.14) -w0 is the angular representation of requency i think it will be 180 -then in above value of alpha will be zero always. -it means Q doesnt have any importantce in filter design -please suggest a good book which describe in detail about filter design It will be 180 what? All angles above are in radians. 'w' (or ω) is for radians/second. For cycles/second (Hz), it's 'f'. One cycle is 2*pi radians. That pi radians equal 180 degrees doesn't make pi (Π) equal to 180. There's no magic that can make it so. Jerry -->Engineering is the art of making what you want from things you can get. >¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯hi jerry thanx for ur response still i didnt get what u mean?? first off all i'm new to this field. i made another mistake what i meant is in the expresion w0=2*pi*f0 value of pi 1s 180 or 3.14. with regards rammya write
Reply by ●February 10, 20102010-02-10
rammya.tv wrote: ... > thanx for ur response still > i didnt get what u mean?? > first off all i'm new to this field. > i made another mistake > what i meant is in the expresion w0=2*pi*f0 > value of pi 1s 180 or 3.14. > with regards According to one passage in the Bible, pi is three. Various legislators at various times introduced ordinances to set the value of pi at some convenient rational fraction. No ordinance can affect the value of a physical constant. Pi remains 3.1415926535897932384626433832795... despite their efforts. 355/113 comes close. Jerry -- Engineering is the art of making what you want from things you can get.
Reply by ●February 10, 20102010-02-10
On Feb 10, 8:39�am, Jerry Avins <j...@ieee.org> wrote:> > According to one passage in the Bible, pi is three. Various legislators > at various times introduced ordinances to set the value of pi at some > convenient rational fraction. No ordinance can affect the value of a > physical constant.Jerry, pi is a mathematical constant. i wouldn't call it a physical constant, in the sense of the fine-structure constant or the proton- electron mass ratio or any of the other 26 or so dimensionless fundamental physical constants.> Pi remains [approx] 3.1415926535897932384626433832795... > despite their efforts.i dunno. them Republicans are challenging a lot of reality. maybe someday they'll win. r b-j
Reply by ●February 10, 20102010-02-10
Jerry Avins <jya@ieee.org> writes:> [...] > According to one passage in the Bible, pi is three.Where is that? -- Randy Yates % "My Shangri-la has gone away, fading like Digital Signal Labs % the Beatles on 'Hey Jude'" mailto://yates@ieee.org % http://www.digitalsignallabs.com % 'Shangri-La', *A New World Record*, ELO
Reply by ●February 10, 20102010-02-10
robert bristow-johnson wrote:> On Feb 10, 8:39 am, Jerry Avins <j...@ieee.org> wrote: >> According to one passage in the Bible, pi is three. Various legislators >> at various times introduced ordinances to set the value of pi at some >> convenient rational fraction. No ordinance can affect the value of a >> physical constant. > > Jerry, pi is a mathematical constant.Right. My bad.> i wouldn't call it a physical > constant, in the sense of the fine-structure constant or the proton- > electron mass ratio or any of the other 26 or so dimensionless > fundamental physical constants. > >> Pi remains [approx] 3.1415926535897932384626433832795... >> despite their efforts. > > i dunno. them Republicans are challenging a lot of reality. maybe > someday they'll win.Bob, you're real good at making up horror stories. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●February 10, 20102010-02-10
Randy Yates wrote:> Jerry Avins <jya@ieee.org> writes: >> [...] >> According to one passage in the Bible, pi is three. > > Where is that?In the old testament, a the descriptions of a vessel in the Temple. look look look ... 1 Kings 4:23. "And he made a molten sea, ten cubits from the one brim to the other: it was round all about, and its height was five cubits: and a line of thirty cubits did compass it round about." Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●February 11, 20102010-02-11
On Wed, 10 Feb 2010 21:46:32 -0500, Jerry Avins wrote:> Randy Yates wrote: >> Jerry Avins <jya@ieee.org> writes: >>> [...] >>> According to one passage in the Bible, pi is three. >> >> Where is that? > > In the old testament, a the descriptions of a vessel in the Temple. > > look look look ... > > 1 Kings 4:23. "And he made a molten sea, ten cubits from the one brim to > the other: it was round all about, and its height was five cubits: and a > line of thirty cubits did compass it round about." > > JerryClearly written by a fuzzy studies major. -- www.wescottdesign.com
