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I'm simulating an FMCW radar in ADS and to control the VCO I use a ramp generator. I tried the ideal case, now I want to add a ripple to my ramp voltage so I can analyze the effect of a ramp voltage with voltage noise. I don't know how to add ripples to a voltage in ADS. I put a voltage noise source in series with my pulse generator but it shows only the noise in the output and not the noise coupled ramp signal. Could someone help me please on this?

Thanks,

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I don't know how to add ripples to a voltage in ADS

If by ripple you mean a sine wave or triangle wave then generate that signal and your ramp as seperate entities and add them together to produce a composite waveform.

The simplest way to add them is to wire them in series.

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  • \$\begingroup\$ Thanks for your answer, actually what I need to add to the ramp signal is some random noise so I can make it non-ideal and uneven. When I add sine wave generator it doesn't look like noise, and when I add voltage noise source in series with my pulse generator it shows only noise, although the noise amplitude I add is 1mV and my ramp is in the range of volts. \$\endgroup\$ – S.E Jun 23 '17 at 18:05
  • \$\begingroup\$ It looks like it overwrites the actual ramp signal and not added to it! \$\endgroup\$ – S.E Jun 23 '17 at 18:12
  • \$\begingroup\$ @SE Please show your schematic (edit your question to include it). \$\endgroup\$ – The Photon Jun 23 '17 at 18:44
  • \$\begingroup\$ Can you add them using a voltage controlled voltage source with input pins connected to each input source? \$\endgroup\$ – Andy aka Jun 23 '17 at 18:44
  • \$\begingroup\$ Thanks all, I think it is solved. The problem was that in a noise voltage source when I assign 1mV to V_noise I need to consider the noise bandwidth as well. V_noise has a dimension of V/sqrt(Hz). So when I assign 1mV and time step in Envelope simulation is 0.1 nsec it gives a 100V output and I cannot see the ramp! To be able to see the ramp with a noise voltage of 1mV at the output I need to assign 1nV for V_noise. \$\endgroup\$ – S.E Jun 23 '17 at 21:07

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