I am working on the burst qpsk transmit receive with data rate varying from 100 kbps to 1 mbps. My modem works fine for continuous tx & rx with costas loop for carrier recovery and Gardner for timing recovery. But in the case of burst transmission will the same loop filter for timing and carrier recovery work as in continuous tx? My timing recovery blocks are polyphase filter -> Gardner -> loop filter -> interpolation control. My interpolation control (mu) is not constant after the header bits are over? Timing recovery should happen in the header bits and remain constant in the data bits.