Section 702 Of Chapter 1. Competency From California Evidence Code >> Division 6. >> Chapter 1.

. (a) Subject to Section 801, the testimony of a witness concerning a particular matter is inadmissible unless he has personal knowledge of the matter. Against the objection of a party, such personal knowledge must be shown before the witness may testify concerning the matter.
  (b) A witness' personal knowledge of a matter may be shown by any otherwise admissible evidence, including his own testimony.