[Discuss-gnuradio] gr.firdes.band_reject()

[Berndt Josef Wulf]

G'day,

I have a problem using the above function. My assumption is that band_reject 
means the rejection of a portion of a spectrum as used in notch filters. The 
following filter design does not show up the expected notch in the spectrum. 
To the contrary, the spectrum shows a slight increase of the noise contents 
at 1000Hz.

sample_rate = 48000
frequency = 1000
bandwidth = 100


coeffs = gr.firdes.band_reject(
                        1.0,
                        sample_rate,
                        frequency - (bandwidth/2),
                        frequency + (bandwidth/2),
                        50,
                        gr.firdes.WIN_HANN)
filter = gr.fir_filter_fcc(1, coeffs)


The band/low/high pass filters work as expected. I use gr.noise_source and 
fft_sink to verify the design. What am I doing wrong? 

cheerio Berndt