Method and apparatus for differentiating a wireless analog signal from a wireless digitally encoded signal

A method of differentiating a received wireless signal between a wireless analog signal and a wireless digitally encoded signal, wherein said wireless analog signal is characterized by having a Supervisory Audio Tone signal and a bandwidth limited data signal, said method comprising:

• converting said received wireless signal into a baseband signal;
• measuring the energy of a portion of said baseband signal to determine the amount of said SAT signal and generating a first energy signal in response;
• measuring the energy of another portion of said baseband signal to determine the amount of energy of said received wireless signal outside said bandwidth limited data signal and generating a second energy signal in response;
• subtracting said first energy signal by said second energy signal to determine a difference signal;
• comparing said difference signal to a threshold to differentiate said received wireless signal between a wireless analog signal and a wireless digitally encoded signal.

A method of locating a Digital Control Channel of a wireless digitally encoded signal;

• said digitally encoded signal and a wireless analog signal are transmitted in a plurality of channels, said wireless analog signal being characterized by a Supervisory Audio Tone signal and a voice signal having a bandwidth, said method comprising:
• a) selecting one of said plurality of channels;
• b) receiving a wireless signal transmitted in said one channel selected;
• c) converting said received wireless signal into a baseband signal;
• d) measuring the energy of a portion of said baseband signal to determine the amount of said Supervisory Audio Tone signal of said received wireless signal and generating a first energy signal in response;
• e) measuring the energy of another portion of said baseband signal to determine the amount of energy outside said bandwidth and generating a second energy signal in response;
• f) subtracting said first energy signal by said second energy signal to determine a difference signal;
• g) comparing said difference signal to a threshold;
• h) selecting another channel in response to the comparison step and reverting to step b;
• in the event said wireless signal received is said wireless analog signal;
• and
• i) locating said Digital Control Channel based upon said wireless signal received.

A telecommunication apparatus for communicating wirelessly with a base station, wherein said base station transmits a wireless digitally encoded signal in a first of a plurality of channels, a control signal for said wireless digitally encoded signal in a second of said plurality of channels, and a wireless analog signal in a third of said plurality of channels, said apparatus for differentiating between said wireless analog signal and said wireless digitally encoded signal, comprising:

• antenna means for receiving a wireless signal transmitted by said base station in one of said plurality of channels and for generating a received RF signal in response thereto;
• baseband converting means for converting said received RF signal into a baseband signal;
• digitizing means for digitizing said baseband signal into a digitized signal;
• first filter means for filtering said digitized signal to produce a first filtered signal;
• second filter means for filtering said digitized signal to produce a second filtered signal;
• first generating means for generating a first energy signal based upon said first filtered signal;
• second generating means for generating a second energy signal based upon said second filtered signal;
• subtracting means for subtracting said second energy signal from said first energy signal to produce a difference signal;
• and
• means for comparing said difference signal to a threshold and in response thereto for determining either said wireless analog signal or said wireless digitally encoded signal.