The passband of the HBF scales with your data rate. The bandwidth is about 70% of the data rate.
Matt On 01/05/2011 08:03 AM, peng senl wrote:
Hello, I have another question about the bandwidth of the HBF. For a wide band incoming signal, let's say 20MHz, can we still use this HBF to filter for this incoming signal, as the pass band of the HBF is only 0.6MHz. --- On Tue, 1/4/11, Tom Rondeau<trondeau1...@gmail.com> wrote: From: Tom Rondeau<trondeau1...@gmail.com> Subject: Re: [Discuss-gnuradio] Question about the HBF in the DDC To: "peng senl"<pengs...@yahoo.com.cn> Cc: discuss-gnuradio@gnu.org Date: Tuesday, January 4, 2011, 8:31 PM On Tue, Jan 4, 2011 at 1:13 PM, peng senl<pengs...@yahoo.com.cn> wrote: Hello, I get a question about the half band filter in the DDC. I found that the LO (local oscillator) in my daughter board is set at 0.2MHz less than the carrier center frequency, which means that the IF of the output signal is center at 0.2 MHz. I am assuming the NCO in the FPGA is generating a sinusoid at 0.2MHz to mix the IF signal to base band. Then we would get a ase band signal and a high order frequency part at 0.4MHz. But the half band filter after the CIC filter has a pass band of 0.6MHz from the reference materials what I have read. This means that the high order part won't be filtered by the HBF. It's generating a _complex_ sinusoid. It's not modulating the signal like an analog LO but performing complex multiplication. Tom _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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