solution of this is to increase the sampling frequency and to generate a waveform with
more samples. However, this increases the memory size to store the waveforms, which
consequently increases the chip size and power consumption, especially for a
multichannel system. In order to generate waveforms with sufficient samples without
increasing the external memory requirement, interpolation becomes necessary. This
allows extra samples to be added between every two adjacent samples of the stored
waveform during transmitting. A much smaller size of memory may be used to store the
waveform for each channel and therefore make it possible to replace large external
memory with FPGA internal BRAM to reduce both chip counts and power consumption.