Pulse down, at the outset too short (4)

'pulse down at the outset too short' is the definition.
I can't judge whether this definition defines the answer.

'down at the outset too short' is the wordplay.
'at the outset' says to take the initial letters.
'too' becomes 'also' (synonyms).
'short' means to remove the last letter.
The first letter of 'down' is 'd'.
'also' with its last letter removed is 'als'.
'd'+'als'='DALS'

Can you help me to learn more?