The wide receiver joined the AFC West champions earlier this year after coming to the end of his contract with the New England Patriots.
The 32-year-old told the team's official website: "It's been great. I've enjoyed the weather. I've enjoyed my teammates. I've enjoyed the coaches and learning a new system. It's been a very positive experience so far.
"[The other Broncos receivers] do a great job of studying and being on top of everything and making a lot big plays out there. They're a big reason of why I wanted to come here. They're great players and I look forward to going to battle with them.
"There is always room for improvement. It's an ongoing thing and [we have to] just keep on grinding away and really learn the offense and being on top of everything, and getting to a point where there are no mental errors or missed assignments or anything."
Welker made 118 receptions, 1,354 receiving yards and scored six touchdowns for the Patriots last season.