Phase detecting method by analog-to-digital conversion

A method of detecting a phase associated with a sinusoidal signal over a period associated with the sinusoidal signal, the method comprising the steps of:

• sampling the sinusoidal signal at a prescribed sampling frequency thereby generating a plurality of sampling values;
• converting the plurality of sampling values to a plurality of digital values;
• respectively evaluating said plurality of digital values within a first half period and a latter half period of said period of the sinusoidal signal, the evaluation of each half period generating respective resulting digital values;
• and
• determining the phase associated with the sinusoidal signal according to the resulting digital values of the first half period and the latter half period;
• wherein,
• said sampling frequency is about eight times greater than a frequency associated with the sinusoidal signal;
• there are four digital values associated with the first half period and four digital values associated with the latter half period;
• the plurality of digital values are each represented by two bits thereby having a possible value of 00, 01, 10 and 11;
• and,
• wherein one of said first half period and said latter half period is evaluated as a value 0 when the number of digital values having a value of 01 and 00 among the four digital values is at least three and is evaluated as a value 1 when the number of digital values having a value of 10 and 11 among the four digital values is at least three.