The Dalek sound is not a ring modulator.
It is a fast square wave tremolo.

Scroll back in the thread, the pedal I linked to is the exact model used on the show. Definitely a ring modulator.

You can see the ring mod being used at 02:13 : 
 
https://www.youtube.com/watch?v=J76zHmmc1so
 
Before the reboot, the BBC Radiophonic Workshop used a ring modulator made by their in house engineer, and later a EMS Putney VCS3. The carrier was a tape on a loop. Sometimes the tape speed would get switched on accident, so some episodes have the dalek voices pitched noticeably higher.

So would i need to buy a dalek sound software?  or just medal with my sonar 7 pro  effects ?

HI guys went into free vst effects and came  across a dalek effect from quillcom not tried it yet but info is that sounds were taken from sine and ringmode of the real dalek sound so i will add it to my vst effects n sonar and try it out later, hope its as good as it says .

Not really a solution for your purposes, but an interesting page nonetheless:
 
http://webaudio.prototyping.bbc.co.uk/ring-modulator/
 
AMB
 

The Melda ring modulator posted earlier is free, and will do exactly what you want. I'd also pick up the free Softube Saturation Knob. Used together, you get a damn good dalek voice.
 
https://www.meldaproduction.com/MRingModulator
 
https://www.softube.com/index.php?id=satknob