A transmission heard rising (9)
I believe the answer is:
ascending
'a transmission' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Maybe there's a link between them I don't understand?
'heard rising' is the wordplay.
'heard' becomes 'a' (I can't explain this - if you can you should give a lot more credence to this answer).
'rising' becomes 'scending' (scending is a kind of rising).
'a'+'scending'='ASCENDING'
Can you help me to learn more?
(Other definitions for ascending that I've seen before include "Rising" , "Going up" , "Getting up" .)