On 11/02/2011 08:03 PM, Johnathan Corgan wrote:
On Wed, Nov 2, 2011 at 16:43, Marcus D. Leech <mle...@ripnet.com <mailto:mle...@ripnet.com>> wrote:Your assertion that "it does take effect eventually" appears to not be true in reality (at least in this little test graph) (attached).To be clear, the problem appears to be with the block itself. GRC correctly adds the "set_delay" callback spooge.But calling that callback in the C++ code doesn't appear to affect the delay.Changing the delay via the callback changes the history requirements of the block, which will not take effect until the thread executing the work() function returns, and could be hundreds or thousands of items in the future. But it does take effect eventually.One way to change this behavior would be to implement the pattern used in the FIR blocks for when the number of taps changes. Changing the delay would set a flag that the work function could check for and return immediately. However, this wold come a high price, as the work() function currently uses memcpy to move data from the input to the output, and instead you'd have to have an iterative loop with a conditional equality check in the middle.Johnathan
Looking at the code, there's an inline function, set_delay, that calls set_history(). And the SWIG goop appears to be correct.
-- Marcus Leech Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org
delay_test.grc
Description: application/gnuradio-grc
#!/usr/bin/env python ################################################## # Gnuradio Python Flow Graph # Title: Delay Test # Generated: Wed Nov 2 20:17:46 2011 ################################################## from gnuradio import eng_notation from gnuradio import gr from gnuradio.eng_option import eng_option from gnuradio.gr import firdes from gnuradio.wxgui import forms from gnuradio.wxgui import scopesink2 from grc_gnuradio import wxgui as grc_wxgui from optparse import OptionParser import wx class delay_test(grc_wxgui.top_block_gui): def __init__(self): grc_wxgui.top_block_gui.__init__(self, title="Delay Test") _icon_path = "/usr/share/icons/hicolor/32x32/apps/gnuradio-grc.png" self.SetIcon(wx.Icon(_icon_path, wx.BITMAP_TYPE_ANY)) ################################################## # Variables ################################################## self.samp_rate = samp_rate = 200e3 self.delay = delay = 0 ################################################## # Blocks ################################################## _delay_sizer = wx.BoxSizer(wx.VERTICAL) self._delay_text_box = forms.text_box( parent=self.GetWin(), sizer=_delay_sizer, value=self.delay, callback=self.set_delay, label="Delay", converter=forms.float_converter(), proportion=0, ) self._delay_slider = forms.slider( parent=self.GetWin(), sizer=_delay_sizer, value=self.delay, callback=self.set_delay, minimum=0, maximum=10, num_steps=10, style=wx.SL_HORIZONTAL, cast=float, proportion=1, ) self.Add(_delay_sizer) self.wxgui_scopesink2_0 = scopesink2.scope_sink_f( self.GetWin(), title="Scope Plot", sample_rate=samp_rate, v_scale=0, v_offset=0, t_scale=0, ac_couple=False, xy_mode=False, num_inputs=2, trig_mode=gr.gr_TRIG_MODE_AUTO, y_axis_label="Counts", ) self.Add(self.wxgui_scopesink2_0.win) self.gr_throttle_0 = gr.throttle(gr.sizeof_float*1, samp_rate) self.gr_sig_source_x_0 = gr.sig_source_f(samp_rate, gr.GR_COS_WAVE, 25000, 1, 0) self.gr_delay_0 = gr.delay(gr.sizeof_float*1, int(delay)) ################################################## # Connections ################################################## self.connect((self.gr_delay_0, 0), (self.wxgui_scopesink2_0, 0)) self.connect((self.gr_sig_source_x_0, 0), (self.gr_throttle_0, 0)) self.connect((self.gr_throttle_0, 0), (self.gr_delay_0, 0)) self.connect((self.gr_throttle_0, 0), (self.wxgui_scopesink2_0, 1)) def get_samp_rate(self): return self.samp_rate def set_samp_rate(self, samp_rate): self.samp_rate = samp_rate self.wxgui_scopesink2_0.set_sample_rate(self.samp_rate) self.gr_sig_source_x_0.set_sampling_freq(self.samp_rate) def get_delay(self): return self.delay def set_delay(self, delay): self.delay = delay self.gr_delay_0.set_delay(int(self.delay)) self._delay_slider.set_value(self.delay) self._delay_text_box.set_value(self.delay) if __name__ == '__main__': parser = OptionParser(option_class=eng_option, usage="%prog: [options]") (options, args) = parser.parse_args() tb = delay_test() tb.Run(True)
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