Frequency counter

A method for determining when a dominant input RF signal is present at a frequency counter so that a useful frequency measurement can be made of a main periodic RF input signal, said method comprising the steps of:

• (a) periodically sampling said main periodic input RF signal to receive at least two signal samples;
• (b) measuring the signal strength of an entire input RF spectrum of one of said at least two signal samples to produce a reference RF signal strength;
• (c) subsequently measuring the signal strength of an entire input RF spectrum of a second of said at least two signal samples to produce a comparison RF signal strength;
• (d) calculating a difference between the comparison RF signal strength and the reference RF signal strength;
• and
• (e) generating control signals when the difference between the comparison RF signal strength exceeds the reference RF signal strength by a predetermined amount.

A method for distinguishing the frequency of a main periodic RF input signal of interest from the frequency of electrical noise inherent in the main periodic RF signal which becomes more apparent as the main periodic RF signal is amplified, said method also for determining when the main periodic RF input signal is present at a frequency counter so that an accurate frequency measurement can be made, said method comprising the steps of:

• (a) periodically sampling said main periodic RF input signal to receive at least two signal samples;
• (b) measuring the frequency of each said at least two signal samples to acquire at least two frequency measurements;
• (c) calculating a difference in frequency measurements between said at least two frequency measurements and comparing said difference to a preselected amount;
• (d) incrementing a measurement counting register in response to a determination that said difference in frequency determined between said at least two frequency measurements differs by less than a preselected amount so as to generate a first control signal when said measurement counting register equals a predetermined value;
• (e) measuring the signal amplitude of an entire input RF spectrum of one of said at least two signal samples to produce a reference RF signal strength;
• (f) subsequently measuring the signal amplitude of an entire input RF spectrum of a second of said at least two signal samples to produce a comparison RF signal strength;
• (g) calculating a difference between the signal amplitude of the comparison RF signal strength and the reference RF signal strength;
• (h) generating a second control signal when the difference between the signal amplitude of the comparison RF signal strength exceeds the reference RF signal strength by a predetermined amount.

A frequency counter for determining the frequency of a main periodic RF input signal of interest having signal noise, said frequency counter distinguishing the frequency count of said main periodic RF input from the frequency count of the signal noise inherent in said main periodic RF signal which becomes more apparent when said main periodic RF signal is amplified, said frequency counter comprising:

• (a) input means for receiving said main periodic RF input signal;
• (b) amplifying means electrically coupled to said input means for amplifying said main periodic RF input signal to improve the efficiency of said frequency counter in detecting zero crossings;
• (c) periodic sampling means electrically associated with said amplifying means for capturing a plurality of samples of said main periodic RF input signal;
• (d) frequency measuring means electrically associated with said periodic sampling means and said amplifying means for measuring the frequency of each of said plurality of samples of said main periodic RF input signal;
• (e) comparing means electrically associated with said frequency measuring means for calculating a difference in frequency measurements between individual samples of said plurality of samples of said main periodic RF input samples and for comparing said difference in said frequency measurements to a preselected amount;
• (f) control signal generating means electrically associated with said comparing means for enabling said frequency measurements to be displayed in response to a determination that said difference in said frequency measurements is less than the preselected amount;
• and
• (g) frequency display means electrically connected to said control signal generating means for displaying said frequency measurement of said main periodic RF input signal in response to signals generated by said control signal generating means.

A frequency counter for determining when a dominant input RF frequency of interest is present and for determining the frequency of said input RF signal of interest comprising:

• (a) amplitude measuring means for initially measuring the signal strength of an entire input RF spectrum sample of said input RF signal to produce a reference input RF signal strength and for subsequently measuring the signal strength of a subsequent input RF spectrum sample of said input RF signal to produce a measured input RF spectrum;
• (b) comparing means for comparing the signal strength of the measured input RF spectrum with the reference input RF signal strength;
• (c) control signal generating means for generating control signals when the signal strength of the subsequently measured input RF spectrum exceeds the signal strength of the reference input RF signal strength;
• and,
• (d) frequency measuring means for determining the frequency of the dominant input RF signal of interest.

A frequency counter for determining the frequency of a main periodic RF input signal having signal noise, said frequency counter distinguishing the frequency count of said main periodic RF input from the frequency count of the signal noise inherent in said main periodic RF signal which becomes more apparent when said main period RF signal is amplified, said frequency counter comprising:

• (a) signal conditioning means for receiving said main period RF input signal and generating a series of amplified electronic trigger pulses at a frequency equal to that of said RF input signal and at a constant amplitude;
• (b) an electrically controlled main gate electrically coupled to said signal conditioning means for allowing said RF input signal to pass from said signal conditioning means through said main gate, said main gate periodically enabled so as to individually capture at least two samples of said RF input signal, said at least two samples of said RF input signal having a fixed period length;
• (c) frequency measuring means for providing individual frequency measurements of said at least two samples captured, said main gate allowing said at least two samples of said RF input signal to pass to said frequency measuring means;
• (d) a microprocessor including a main gate enabling means and a frequency differentiating means, said main gate enabling means electrically coupled to said main gate for controlling the triggering of said main gate at a predetermined rate so as to capture individually said at least two samples having a fixed period length, said frequency differentiating means electrically coupled to said frequency measuring means for temporarily storing said frequency measurements of said at least two samples and computing a difference between said frequency measurements so as to differentiate between a frequency measurement of said RF input signal and said signal noise, said microprocessor including a frequency display enabling means for enabling a frequency display to display a correct reading of said RF signal input.