I have a sinusoid in continuous time, with a frequency of 18kHz, it is sampled ideally with a continuous to discrete convertor, with a frequency of 27kHz. After that, we change the sampling speed in discrete time, using interpolator system and decimate system,so that result frequency equivalent in discrete time is 13.5KHz.
The interpolation factors and decimation factors are:
a) I=3 and D=2.
b) I = 1 and D=2
c) I= 3 and D=4
d) I = 4 and D = 3
I see this example on the internet and I don't know what is the correct one. Can you please help me to know what is the true answer and how it is calculated?