Yes, it is required to have a Savings Bank Account to open a demat account.
Mainly 3 documents with Photo and signature are required :
PAN, Address Proof and Bank details (A/c No., IFS Code and MICR) that is also works as income proof.
Demat Account: This is an account which holds physical shares in electronic form and this called dematerialisation.
As we know that a bank account is needed for monetary transactions.
Likewise, a demat account is needed for holding securities in electronic form and are credited/debited accordingly.
But for all purchases and sells one needs a bank account that will be mapped to the Demat account so that an investor can credit money to the trading account and debit the same accordingly.
A bank account also serves the purpose of income proof.