What is the difference between a conviction and acquittal in a perjury case?

Subsequently, the jury returned a verdict acquitting appellee of the first specification of perjury, but convicting him of the second. A motion for a new trial based on allegedly erroneous evidentiary rulings was denied from the bench, and approximately two weeks thereafter, the court in a written opinion rejected the claim that the government had failed to fulfill its duty under Brady v. Maryland, 373 U.S. 83, 83 S.Ct. 1194, 10 L.Ed.2d 215 (1963), in that it withheld from the defendant an allegedly exculpatory document. On the date scheduled for imposition of sentence, however, the court, apparently acting sua sponte, declared that the statements set forth in the second specification of perjury, to the extent they were not repetitive of the first specification, were immaterial to the grand jury's investigation. The court, in pertinent part, stated: