This paper focuses on the stochastic Cramer-Rao bound (CRB) of direction of arrival (DOA) estimates for binary phase-shift keying (BPSK) and quaternary phase-shift keying (QPSK) modulated signals corrupted by additive circular complex Gaussian noise. Explicit expressions of the CRB for the DOA parameter alone in the case of a single signal waveform are given. These CRB's are compared, on the one hand, with those obtained with different a priori knowledge, and on the other hand with CRB's under the non-circular and circular complex Gaussian distribution and with different deterministic CRB's. It is shown in particular, that the CRB's under the non-circular [resp. circular] complex Gaussian distribution are tight upper bounds on the CRB's under the BPSK [resp. QPSK] distribution at very low and very high signal to noise ratios (SNR) only. Finally, these results and comparisons are extended to the case of two independent BPSK or QPSK distributed sources where an explicit expression of the CRB for the DOA parameters alone is given for large SNR.