New York Consolidated Laws, Criminal Procedure Law - CPL § 450.30 Appeal from sentence

1. An appeal by the defendant from a sentence, as authorized by subdivision two of section 450.10, may be based upon the ground that such sentence either was (a) invalid as a matter of law, or (b) harsh or excessive.  A sentence is invalid as a matter of law not only when the terms thereof are unauthorized but also when it is based upon an erroneous determination that the defendant had a previous valid conviction for an offense or, in the case of a resentence following a revocation of a sentence of probation or conditional discharge, upon an improper revocation of such original sentence.  An appeal by the defendant from a sentence, as authorized by subdivision three of section 450.15, may be based upon the ground that such sentence was harsh or excessive.

2. An appeal by the people from a sentence, as authorized by subdivision four of section 450.20, may be based only upon the ground that such sentence was invalid as a matter of law.

3. An appeal from a sentence, within the meaning of this section and sections 450.10 and 450.20, means an appeal from either the sentence originally imposed or from a resentence following an order vacating the original sentence.  For purposes of appeal, the judgment consists of the conviction and the original sentence only, and when a resentence occurs more than thirty days after the original sentence, a defendant who has not previously filed a notice of appeal from the judgment may not appeal from the judgment, but only from the resentence.

4. When as a result of a successful appeal by the people from a sentence, the defendant receives a resentence the terms of which are more severe than those of the original or reversed sentence, the defendant, if he has not taken an appeal from the judgment, may, even though the period for doing so as prescribed in section 460.10 has expired, take such an appeal by filing and serving a notice of appeal, or an affidavit of errors as the case may be, within thirty days after imposition of the resentence.  Upon such an appeal, only the conviction is reviewable;  and any appellate challenge to the resentence must be made upon a separate appeal therefrom.