hi jason, you asked about CIC filters:
VEGAS has modes where the fpga extracts 8 subbands from a 1.5 GHz band, with selectable bandwidth, and selectable center frequencies. the eight time domain sub bands are packetized (8 bit real, 8 bit imag) and are sent to a GPU for high resolution spectroscopy. for each of the 8 sub-band downconverters, the fpga implements a real to complex baseband downconverter, (5 Gsps ASIAA ADC --> IQ mixer, where the sin/cos LO is generated by sequencing through a look up table (a counter driving the address port of a dual port ram which contains sin/cos waveforms)) the mixers are followed by multistage decimating CIC filters (16 filters for the 8 sub-bands). i think hong chen developed and tested the multistage CIC filters for vegas, and they have been improved by the folks at green bank. i'm not sure where the most recent FPGA code is. hopefully randy, luke and the folks at green bank can help with this if you are interested. best wishes, dan Dan Werthimer Marilyn and Watson Alberts Chair Astronomy Dept and Space Sciences Lab University of California, Berkeley On Thu, Jun 27, 2019 at 7:51 AM Jason Manley <jman...@ska.ac.za> wrote: > Hi CASPERites > > Has anyone implemented a decimating CIC filter on a CASPER platform? How > 'bout a conventional IIR or FIR filter? We're after ones that accept > parallel input samples; the Xilinx one doesn't seem to do wideband signals. > > We're looking at options for a new digital downconverter. Please let me > know if you've got something you could share with us to use. If not, we'll > have to start modding the PFB_FIR and existing DDC library blocks for our > needs. > > Jason Manley > DSP Manager > SKA-SA > > Cell: +27 82 662 7726 > Work: +27 21 506 7300 > > -- > You received this message because you are subscribed to the Google Groups " > casper@lists.berkeley.edu" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to casper+unsubscr...@lists.berkeley.edu. > To view this discussion on the web visit > https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/C3DB0FD8-7B14-4232-B266-E7E17930AD89%40ska.ac.za > . > -- You received this message because you are subscribed to the Google Groups "casper@lists.berkeley.edu" group. To unsubscribe from this group and stop receiving emails from it, send an email to casper+unsubscr...@lists.berkeley.edu. To view this discussion on the web visit https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CAGHS_vGHm_pjzU2BwbwPqc3kN24708Oa4MKBP6r4xBZhw_hgfA%40mail.gmail.com.
