  The Tianlai Dish Pathfinder array is a radio interferometer array consisting
of 16 six meter dish antennas. The original digital backend integration time is
at the seconds level, designed for HI intensity mapping experiment. A new
digital backend with millisecond response is added to enable it to search for
fast radio burst (FRB) during its observations. The design and calibration of
this backend, and the real time search pipeline for it are described in this
paper. It is capable of forming 16 digital beams for each linear polarisation,
covering an area of 19.6 square degrees. The search pipeline is capable of
searching for, recording and classifying FRBs automatically in real time. In
commissioning, we succeeded in capturing the signal pulses from the pulsars PSR
B0329+54 and B2021+51.
