On Jun 11, 8:20 pm, Jerry Avins <j...@ieee.org> wrote:> I think he wants to know the difference between a complex filter (that > obviously has real and imaginary parts) and two filters, one for the > real part of the signal and another for the imaginary part. Do do I.cross products
Equalizer
Started by ●June 11, 2007
Reply by ●June 12, 20072007-06-12
Reply by ●June 12, 20072007-06-12
On Jun 12, 12:22 am, "Ron N." <rhnlo...@yahoo.com> wrote:> On Jun 11, 8:20 pm, Jerry Avins <j...@ieee.org> wrote: > > > I think he wants to know the difference between a complex filter (that > > obviously has real and imaginary parts) and two filters, one for the > > real part of the signal and another for the imaginary part. Do do I. > > cross productsExactly. In the output of a complex filter, there will be some terms that are proportional to the product of the imaginary part of the coefficients and the real part of the input, and vice versa. This is a product (no pun intended) of the complex multiplication involved in calculating the output. If you do two separate real filters and sum their outputs, you don't get these cross terms, so the overall response is not the same as the complex filter. Jason
Reply by ●June 12, 20072007-06-12
Jerry Avins wrote:> I think he wants to know the difference between a complex filter (that > obviously has real and imaginary parts) and two filters, one for the > real part of the signal and another for the imaginary part. Do do I.The equalizer must be the analytical function, i.e. it has to satisfy the Cauchy-Riemann conditions. I.e. the complex combination of the real filters is analytical only for the trivial cases. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
Reply by ●June 12, 20072007-06-12
Ron N. wrote:> On Jun 11, 8:20 pm, Jerry Avins <j...@ieee.org> wrote: >> I think he wants to know the difference between a complex filter (that >> obviously has real and imaginary parts) and two filters, one for the >> real part of the signal and another for the imaginary part. Do do I. > > cross productsAha! Jerry -- Engineering is the art of making what you want from things you can get. ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
