Systems and methods for color Doppler imaging in an ultrasound imaging system are disclosed herein. An ultrasound imaging system includes color Doppler imaging circuitry. The color Doppler imaging circuitry is configured to estimate flow parameters. The imaging circuitry includes a radio frequency (“RF”) demodulator configured to produce in-phase and quadrature components of an ultra-sound data vector. The RF demodulator includes a table in memory that stores interleaved sine and cosine values. The RF demodulator maintains an index value for the table having higher precision than is used to index the table. The RF demodulator rounds the index value for each access of the table. Each table access retrieves a sine value and a cosine value.