At any time in any budget year, when Council shall determine that revenues will, for any reason, be insufficient to meet authorized expenditures, it may, by ordinance, direct the issuance of notes. These notes may be of three (3) different types:
(1) Those issued to finance emergency appropriations under Section 7.12 of this Charter, when unappropriated available revenues are insufficient for that purpose;
(2) Those issued in anticipation of the collection of taxes upon real estate and personal property; and
(3) Those issued in anticipation of the collection of other types of revenue.