# What is the difference between upsampling and up conversion (done during signal transmission)? Also is upconversion different from modulation?

Up sampling is when you increase the sample rate of a continuous signal. Modulation is when you, by multiplying with a carrier, shift the base frequency of a signal. But what is up conversion? How is it related with the above mentioned terms?

• In digital communications, modulation is the mapping from bits to symbols (pulse amplitudes). For example, in BPSK modulation one maps a bit 0 to an amplitude $A$, and a bit 1 to an amplitude $-A$. Upconversion means shifting the analog baseband modulated signal up to radio frequency for transmission. – MBaz May 12 '15 at 11:40