Describe two different currency systems that have been introduced in countries such as Hong Kong and Ecuador

Question:

Describe two different currency systems that have been introduced in countries such as Hong Kong and Ecuador to improve the credibility of pegged systems.

Exchange Rate
The value of one currency for the purpose of conversion to another. Exchange Rate means on any day, for purposes of determining the Dollar Equivalent of any currency other than Dollars, the rate at which such currency may be exchanged into Dollars...