Method and apparatus for determining signal strength in a variable data rate system

An apparatus providing a signal strength estimate comprising:

• a demodulation element having an output producing a series of symbol energies corresponding to a data signal of an unknown data rate;
• a summation register having an input coupled to said demodulation element output, having an enable input, and having an output producing a sum of a plurality of said series of symbol energies conditioned upon a signal received by said enable input;
• an active group clock having an output coupled to said enable input of said summation register, said output producing an indication of a group of said series of symbol energies corresponding to symbols containing data independent of said unknown data rate of said data signal;
• a first-in-first-out storage register having an input coupled to said summation register output and having a plurality of outputs each producing an indication of a previous value of said sum at said output of said summation register;
• and
• an adder having a plurality of inputs coupled to each of said plurality of outputs of said first-in-first-out storage register and having an output producing said signal strength indication.