There is difference of voters and constituency between the system of reservation of constitution and the system of separate electorate. It was started by the British government that the Muslims, Sikhs and some other minorities were able to elect their representatives by their own separate vote. As a result the nation resorted to the partition between India and Pakistan. So, after partition, in India, the reservation of constituencies for the subjugated social group was adopted.
In separate electorates, the candidates are elected by those voters who belong to that community. But in the system of reservation of constituencies all voters in a constituency are eligible to vote but candidates must fit in to only a particular community for which the seat is reserved. The constitution provides for reservation of seats in the Lok Sabha and State Legislative Assemblies for the Scheduled Castes and Scheduled Tribes.
The latter was rejected by the constitution makers because it went against their idea of unity they were aware that the system of separate electorate will damage the spirit of national integration and a state free from discrimination.