A bit error rate (BER) measuring apparatus is provided for measuring BER of an out-of-band tuner. The BER measuring apparatus generates a test signal for measuring the BER of the out-of-band tuner using a transport stream including a pseudo-random bit string (PRBS). In one embodiment, the BER measuring apparatus comprises a BER test signal generator that generates the test signal which includes a transport stream for transmission. The BER measuring apparatus also comprises a BER detector that detects the BER from a received test signal generated by the tuner in response to the test signal from the BER test signal generator. In one embodiment, the test signal generator comprises a PRBS generator that generates a first PRBS, and a transport stream framing circuit that frames the first PRBS into a transport stream form to generate the transport stream for transmission.