The Prime Minister, who will attend a Conservative rally in Perth, will echo his predecessor Gordon Brown's recent declaration that voting against the break-up of Britain and for a stronger Scotland within the UK was the "proud and patriotic" thing to do.
Mr Cameron will say: "We have heard the noise of the Nationalist few, but now it is time for the voices of the silent majority to be heard.
"The silent majority, who feel happy being part of the UK; the silent majority who don't want the risks of going it alone; the silent majority who worry about what separation would mean for their children and grandchildren."
With just 76 days to go until the referendum, the PM will insist the voices of the many need to "ring out across the land" and that each one should realise there are millions just like them.
"This is how we rouse them to find their voice. We tell them: we've achieved so much together; we're safer together; we're better off together; we've got the best of both worlds together."
Mr Cameron will also insist it is not anti-Scottish to reject independence and vote to stay within the UK.
He will add: "Too many people in this country have been made to feel you can't be a proud Scot and say 'No thanks'; you've got to choose between the Saltire and the Union flag. That is wrong.
"Loving your country means wanting the best for it and, for Scotland, that is staying in the UK. So yes, you can be a patriotic Scot and vote No."
During Prime Minister's Question Time yesterday, Mr Cameron accused Alex Salmond's government of intimidation, telling MPs: "A huge amount of pressure is put on businesses by the Scottish Government, with all sorts of threats and warnings if they speak out and say what they believe is the truth.
"I come across business leader after business leader, large and small, in Scotland who want to keep our UK together, who think it would be crazy to have border controls, different currencies and split up our successful UK."
A spokesman for Finance Secretary John Swinney said the claims were "untrue", adding: "It is Mr Cameron's government that has very serious questions to answer about what appear to have been referendum-related attempts to intimidate and bully leading companies that depend on Ministry of Defence orders and contracts."
Gordon MacIntyre-Kemp, chief executive of Business For Scotland, accused Mr Cameron of peddling the "same old tired UK line" about firms being afraid to speak up when 2200 of the pro-independence body's members were speaking up about "the opportunities independence will bring".
It comes after Paisley and Renfrewshire North Labour MP Jim Sheridan had suggested employers had a "moral responsibility" to inform their workers of the consequences of independence .
Scottish Secretary Alistair Carmichael said businesses had told him they were "finding it next to impossible to get access to finance for commercial property development in the north-east of Scotland because of the uncertainty surrounding the referendum".
Meanwhile, City of London lawyers say independence would bring a "tsunami of work", with the potential of Scottish banks moving to London and a glut of legal work generated by changing regulations. John Hanley, a director at Nord Landesbank, said: "There are a number of institutions in the City deliberately not investing in Scotland until the uncertainty is removed after the referendum."