Automatic gain control for digitized RF signal processing

A method of processing an RF input signal, comprising the steps of:

• (a) receiving an RF signal;
• (b) inputting the RF signal to an attenuator to produce an attenuator output;
• (c) applying the attenuator output to an amplifier while controlling a variable gain in the attenuator to produce a controlled amplified output;
• (d) passing the amplified output through a bandpass filter to produce a filtered RF output;
• (e) applying the filtered RF output to an ADC to produce a digitized output signal;
• (f) applying the digitized output signal to a signal detection logic to determine an attenuation value and to produce a delayed output signal;
• (g) repeating steps (a)-(f) for each of a plurality of ADC data samples;
• (h) establishing a threshold for detecting the presence of a pulse within the plurality of ADC data samples;
• (i) applying the delayed output signal to a buffer to produce a buffered signal output;
• and
• (j) applying the attenuation value to the attenuator to establish an updated attenuation gain value.

An automatic gain control RF signal processor, comprising:

• an attenuator having an input for receiving an analog RF input signal, an output for applying an attenuated output signal, and a variable gain control input;
• an amplifier having an input coupled to the attenuator output and an output;
• a bandpass filter having an input coupled to the amplifier output and an output;
• a single ADC having an input coupled to the bandpass filter output and an output for providing a digitized ADC signal;
• a FIFO buffer having an input and an output for producing an attenuated, gain control, digitized output;
• and
• a digital logic circuit having an input for receiving the ADC signal, a first output coupled to the variable gain control input of said attenuator, and, a second output coupled to the buffer input, said digital logic circuit including signal detection logic, and said signal detection logic comprising:
• a threshold logic for detecting the presence of a pulse within the ADC signal;
• and
• a control logic for determining a peak amplitude value of the pulse, and based on the peak amplitude value generating an attenuation value at said first output that is applied to the variable gain control input of said attenuator, said control logic further controlling a flow of data into the buffer.

An automatic gain control RF signal processor, comprising:

• amplifying and gain control means for amplifying an analog RF input signal and controlling the gain of said RF input signal;
• a bandpass filter having an input coupled to the amplifying and gain control means and an output;
• a single ADC having an input coupled to the bandpass filter output and an output for providing a digitized ADC signal;
• a digital logic circuit having an input for receiving the ADC signal, a first output coupled to the variable gain control input of said attenuator, and a second output, said digital logic circuit including signal detection logic for detecting the presence of a pulse within the ADC signal, determining a peak amplitude value of the pulse, and based on the peak amplitude value generating an attenuation value at said first output that is applied to the variable gain control input of said attenuator;
• and
• buffer means having an input coupled to the second digital logic circuit output and an output for producing an attenuated, gain controlled, digitized output.