When is "deflation" most likely to occur in the business cycle?

In economics, deflation can be described as a decrease in the general price level of goods and services or currency appreciation with respect to the same goods and services. Deflation occurs when the inflation rate falls below 0% (a negative inflation rate). Inflation reduces the real value of money over time; conversely, deflation increases the real value of money - the currency of a national or regional economy. This allows one to buy more goods and services than before with the same amount of money.