Patent ID: 7957459

Claim:
A symbol rate testing method, comprising: receiving a signal with a plurality of quasi bits and sampling the signal within an acquiring time; calculating a sampled value of the signal at each sampling point; obtaining a critical value among the sampled values; and determining whether each of the quasi bits is a predetermined bit according to the critical value, and counting a number of the bits within the acquiring time to obtain a symbol rate, wherein the critical value among the sampled values is a minimum value among maximum values of all quasi bits 1 , or a maximum value among minimum values of all quasi bits 0 , when the quasi bit is a quasi bit 1 , obtaining the maximum value of the quasi bit 1 further comprises: (a) reading a currently, a previously, and a second previously sampled values; (b) when the currently sampled value is greater than the previously sampled value, reading a next sampled value as a new currently sampled value; otherwise, setting the previously sampled value as a maximum value, and reading a next sampled value; and (c) when the next sampled value is smaller than the previously sampled value thereof, reading a next sampled value as a new currently sampled value; otherwise, performing the following determination: when the next sampled value is greater than the previously value thereof and the next sampled value is smaller than the maximum value, setting a maximum value of the quasi bit 1 as the maximum value; otherwise, reading a next sampling point; when the next sampled value is smaller than 0 and the previously sampled value thereof is greater than 0, setting a maximum value of the quasi bit 1 as the maximum value; otherwise, reading the next sampling point; when the next sampled value is greater than the previously sampled value thereof, reading the next sampling point.