The Bluebirds have signed striker Frederic Gounongbe and defender Jazz Richards (pictured) so far this summer, as well as making the loans of Lex Immers and Kenneth Zohore permanent transfers.
Cardiff's opening Championship fixture is at Birmingham on Saturday, 6 August.
"There's time and I'm sure there'll be a lot of business between now and when the window shuts," said Trollope.
"We're still looking and we're still hopeful."
Cardiff concluded their pre-season preparations with a 1-0 defeat away against Premier League side Bournemouth on Saturday.
Gounongbe led the attack in a 3-4-2-1 formation based on the system which Wales used as they reached their first major tournament semi-final at Euro 2016.
The 28-year-old joined on a free transfer from Westerlo having scored 13 goals for the Belgian side last season.
The Benin international and the relatively inexperienced 22-year-old Zohore are the only recognised strikers in the current Cardiff squad likely to feature this season.
But Trollope would not be drawn when he was asked if attack is an area of the team he is aiming to strengthen in particular.
"I'm not going to go into details in terms of what we're looking for," he said.
"But we're looking at certain areas we think we need to strengthen and add, both in terms of the first team and competition for places and strength in depth which we obviously need."
The other two strikers at Cardiff, Federico Macheda and Adam Le Fondre, have been told they are free to leave if they can find a new club.
"We've got interest in a few of ours who we've made available," added Trollope.
"We've been respectful to them and they've worked hard whichever group they've been with, if we can find a solution that would suit all parties."