Is a waiver of constitutional rights as to a prior conviction sufficient?

Appellant contends that his waivers of constitutional rights as to the second alleged prior conviction were insufficient because the record does not reflect that appellant understood his rights and the meaning of the waivers. Here the district attorney specifically asked appellant if he was waiving his right to jury trial, his right to confront and cross-examine witnesses, and his privilege against self-incrimination. The admonition, while minimal, was sufficient. (Cf. People v. Balderrama (1990) 221 Cal.App.3d 282, 286-288, 270 Cal.Rptr. 432.)