The principle of the double jeopardy as it manifests in article 20 (2) basically is related to the concept that excessive restrain upon the personal liberty cannot be put and therefore if the accused has been prosecuted or punished for offense one then he cannot be prosecuted or punished for the same offense again. The same offense here means the same conduct which amounts to be an offense.
The focus of article 20 (2) is upon the multiplicity of the punishment through multiple prosecutions for the application of article 20 (2), it shall be proved that the earlier prosecution and punishment was either by a judicial authority or by Quasi-judicial authority by process of the prosecution and does if the accused has suffered determent earlier in the departmental disciplinary action or any other similar action then it will not be the case of article 20 (2) as same cannot be set to be a prosecution for the purpose of article 20 (2). Section 300 of CrPC 1973, prohibited the retrial of accused one the accused has been trialed and either convicted or acquitted by the competent court.
As long as the judgment of that courts remains in the force it does not prohibits appellate proceeding rather than the prohibition is upon the second trial in the original jurisdiction. The logic is that when the accused was already trialed and convicted or acquitted on merit then unless the appellate court set aside the judgment and remands the case to the competent court for retrial there is no logic having another trial of the same case in the original jurisdiction.
Section 300 of CrPC 1973, aims at avoiding wastage of time and multiplicity of prosecution of the accused, such multiple prosecutions is a peril to the accused and hence to that extent section 300 can be said to carrying forward the spirit of article 20 (2) by preventing Double Jeopardy in the process of multiple prosecutions.
However, section 300 of CrPC 1973, cannot be said to the same as article 20 (2) will apply only in case of punishment whereas Section 300 of CrPC 1978, applies even in the case of acquittal in the earlier prosecution.