A warrant of arrest shall specify the name of the defendant or, if it is unknown to the magistrate, judge, justice, or other issuing authority, the defendant may be designated therein by any name. It shall also state the time of issuing it, and the city or county where it is issued, and shall be signed by the magistrate, judge, justice, or other issuing authority issuing it with the title of his office and the name of the court or other issuing agency.