Generic transmitter for audio reciever?

Just picked up 8 of these wireless receivers(audio-technica atw-r2100) intended for receiving audio signal from wireless microphones.

I would like to set up a system that transmits a signal from my main sound system to these units around the house.

The product specs page says it receives primarily on UHF Band D: 656.125 to 678.500 MHz.

Is there a generic transmitter that would connect to these receivers?

Let me know if you have a recommendation for a sub that might be more knowledgeable for this question.

(https://www.audio-technica.com/en-us/microphones/wireless-systems/line-series/2000-series)s