I am wonder if any of you know the best way to make an audio tracks volume cut in and out to the tempo of the song.  Linked below is some audio of a song with the effect Im looking for.  This artist uses it mostly with different synth sounds..  It's almost like a choppy arpeggiator sound.  Volume plugin?  Arpeggiator?  WahWah?   THX
 
 starts at :38 seconds
https://www.youtube.com/watch?v=OrCfzftEXig&feature=kp

Couldn't access your clip (?), but three suggestions.
 
1. Drive the Sonitus Gate sidechain by a drum part that creates the kind of "chop" you want. I describe this technique in the Sonar video I did at Berklee last month.
2. This is really cool, but it doesn't seem to be a very well-known feature: right-click on the Draw tool (the one you select by typing F9) and you can select a periodic waveform. Use something like a square wave to drive volume automation. The waveform frequency is set by the snap to grid setting.
3. Sometimes I just go in and cut/delete selectively. I wanted to emulate flicking a kill switch on a guitar, and that can't be a regular gating.

Soundcloud blocked the Paul Hardcastle audio.. but I will try that Craig.. Thx!  ; )

Updated the link ; )
 

Craig,
 
I got the desired choppy synth sound I want, but I do not want to hear the drum sound that is driving the sidechain.. how is this done? I have it set up like this..
- Track 1:  audio HiHat (being sent to Sonitus gate)
- Track 2:  Audio Synth sound (With Sonitus Gate on track)
 
I tried freezing track 2, which didn't capture the Sidechain effect.  Thx  ; )

Use a pre-fader send from track 1 to the gate and turn the fader down on the track or use the track output to the gate instead of a send.

Yep, clicking the fader from "post" to "Pre" did the trick.. thanks Scook! 

I know this question is answered but for a more severe choppy effect you can try illformed dot com's glitch plug in. They Still have the free 1.3 version available. Try retrigger effect. Not what you asked for but it is a fun option with different sound than side chain pumping.

You can also do this sort of thing in Guitar Rig by hooking up a step sequencer to a volume pedal:
 
1) Insert a volume pedal (Dynamics) into the effect chain followed by a step sequencer (Modifier) 
2) Set the volume pedal to something like halfway
3) Make sure all of the steps on the step sequencer are selected (blue). 
4) Drag the assignment handle (sort of cross shape next to where it says "STEP SEQ") on the step sequencer to the slider on the volume pedal
5) Access the assignment sliders on the step sequencer by clicking the little downward triangle on the far right of the unit
6) Make sure the volume pedal assignment slider is all the way to the right
 
And that's it! All you have to do now is adjust the settings on the step sequencer (resolution, attack, decay, width and offset) to get the choppiness you need. It's very versatile. You can also drag the assignment slider all the way to the right for a slightly different timing (but make sure you adjust the width control after doing it). Try turning some of the steps off for more rhythmic variation. 
 
It's really quick and easy to set up once you learn the drill. I've gone as far as to have up to 4 step sequencers in the chain, all assigned to the volume pedal and all with different rhythms, which I automated on/off in Sonar to get different glitch patterns. And don't forget you can hook up these step sequencers to any effect in Guitar Rig. It's a shame that more people don't take the time to learn how these modifiers work, because they have loads of potential for making complicated rhythm-based effects.