Frequency measuring apparatus

Claim 2

Apparatus for measuring the unknown frequency of a periodically varying signal comprising a local oscillator means for generating a periodically varying signal of known frequency, a heterodyning means having first and second inputs and an output for heterodyining the signals received at said inputs and transmitting a signal having a frequency which is the difference in the frequencies of the signals received at said inputs, said first input being adapted to receive the signal whose frequency is to be measured, said second input being connected to said local oscillator means, a signal cycle counter means for counting cycles of a periodically varying signal, said cycle counter means having an input, and means for sequentially connecting the input of said cycle counter means to said local oscillator means for a first given period of time and to the output of said heterodyning means for another given period of time.

Claim 3

The apparatus of claim 1 wherein said periods of time are the same.

Claim 4

The apparatus of claim 1 wherein said means for connecting said oscillator means to said second input of said heterodyning means includes means whereby the known frequency of the periodically varying frequency is changed by a factor M and where said one given period of time is M times as long as said other given period of time.

Claim 5

The apparatus of claim 1 wherein said sequentially connecting means comprises means for generating sequential first and second gating signals, first and second signal gating means each having a cyclic signal input, a gating signal input and an output, means for connecting the outputs of each of said gating means to the input of said cycle counter means, means for connecting the input of said first gating means to said local oscillator means, means for connecting the input of said second gating means to the output of said heterodyning means and means for connecting the gating signal inputs of said gating means to said gating-signal-generating means in a manner that said first gating means receives the first gating signal and said second gating means receives the second gating signal.

Claim 6

The apparatus of claim 4 wherein said means for connecting said oscillator means to said second input of said heterodyning means includes means whereby the known frequency of the periodically varying frequency is changed by a factor M and where said one given period of time is M times as long as said other given period of time.

Claim 7

Apparatus for measuring the unknown frequency of a periodically varying signal comprising a local oscillator means for generating a periodically varying signal of known frequency, a heterodyning means having first and second inputs and an output for heterodyning the signals received at said inputs and transmitting a signal having a frequency which is the difference in the frequencies of the signals received at said inputs, said first input being adapted to receive the signal whose frequency is to be measured, said second input being connected to said local oscillator means, a signal cycle counter means for counting cycles of a periodically varying signal, said cycle counter means having an input, means for presetting said cycle counter means to a particular count related to the number of cycles of the signal generated by said local oscillator means in a given period of time and means for connecting the input of said cycle counter means to the output of said heterodyning means for another given period of time.

Claim 8

Apparatus for measuring the unknown frequency of a periodically varying signal comprising a local oscillator means for generating a periodically varying signal of known frequency, a heterodyning means having first and second inputs and an output for heterodyning the signals received at said inputs and transmitting a signal having a frequency which is the difference in the frequencies of the signals received at said inputs, said first input being adapted to receive the signal whose frequency is to be measured, said second input being connected to said local oscillator means, a signal cycle counter means for counting cycles of a periodically varying signal, said cycle counter means having an input, means for presetting said cycle counter means to a particular count related to the number of cycles of the signal generated by said local oscillator means in a given period of time and means for connecting the input of said cycle counter means to the output of said heterodyning means for another given period of time.