hourly value to copy the same value every 15 minutes

[voltages]

i have this column of numbers which is recorded every hour. i want to put a formula on the next column that converts the hourly data to 15 minute data, how will it be done?

ex

4 4
20 4
34 4
4
20
20
20
20
34
34
34
34

so in the next column four cells will have the same value then so on going down.

volt

 

[voltages]

or how to automatically put a formula in column B that will look like this

=A1
=A1
=A1
=A1
=A2
=A2
=A2
=A2
=A3
=A3
=A3
=A3
on so on
=