Variable frequency missing pulse detector

Claim 2

A missing pulse detector for detecting a loss of signal from a variable frequency source, comprising: reference signal generator means responsive to said variable frequency source signal for generating a reference signal having a frequency proportional to the average frequency of said variable frequency signal, said reference signal generator means being substantially insensitive to the lost cycle of said variable frequency source signal, said reference signal generator means including a frequency-to-voltage converter and a voltage-to-frequency converter connected in series, one of said converters receiving said source signal, said reference signal being an output of the other of said converter means for generating non-delayed test pulses in response to cycles of said variable frequency source signal and with a repetition rate substantially equivalent to the frequency of the variable frequency source signal; and warning circuit means responsive to said test pulses and to said reference signal for producing a warning signal in response to a loss of said variable frequency source signal.

Claim 3

The missing pulse detector of claim 1, wherein said warning circuit comprises: a first bistable device having an output with a first state triggered by the reference signal and with a second state triggered by the test signal; first gate means for producing an output signal unless the reference signal and the output of the first bistable device are in a selected state; a second bistable device having an output with a first state triggered by the output signal of the first gate means and with a second state triggered by the test signal; and second gate means for producing said warning signal when the reference signal and the output of the second bistable device are in a selected state.

Claim 4

The missing pulse detector of claim 1, wherein said test pulse generating means comprises monostable means for generating a test signal in response to a predetermined condition of the variable frequency source signal.

Claim 5

The missing pulse detector of claim 3, wherein said warning circuit means comprises bistable means and gate means coupled to said reference signal and to said test pulses for producing said warning signal upon the loss of said variable frequency source signal.

Claim 6

The missing pulse detector of claim 4, wherein: said frequency-to-voltage converter receives said variable frequency source signal, said reference signal being an output of said voltage-to-frequency converter.

Claim 7

A missing pulse detector for detecting a loss of signal from a variable frequency source, comprising: reference signal generator means responsive to said variable frequency source signal for generating a reference signal having a frequency proportional to the average frequency of said variable frequency source signal, said reference signal generator means being substantially insensitive to a lost cycle of said variable frequency source signal; means for generating non-delayed test pulses in response to cycles of said variable frequency source signal and with a repetition rate substantially equivalent to the frequency of the variable frequency source signal, said test pulse generating means including monstable means for generating a test signal in response to a predetermined condition of the variable frequency source signal; and warning circuit means responsive to said test pulses and to said reference signal for producing a warning signal in response to a loss of said variable frequency source signal, said warning circuit means including bistable means and gate means coupled to said reference signal and to said test pulses for producing said warning signal upon the loss of said variable frequency source signal.

Claim 8

A missing pulse detector for detecting a loss of signal from a variable frequency source, comprising: reference signal generator means responsive to said variable frequency source signal for generating a reference signal having a frequency proportional to the average frequency of said variable frequency source signal, said reference signal generator means being substantially insensitive to a lost cycle of said variable frequency source signal; means for generating non-delayed test pulses in response to cycles of said variable frequency source signal and with a repetition rate substantially equivalent to the frequency of the variable frequency source signal, said test pulse generating means including monstable means for generating a test signal in response to a predetermined condition of the variable frequency source signal; and warning circuit means responsive to said test pulses and to said reference signal for producing a warning signal in response to a loss of said variable frequency source signal, said warning circuit means including bistable means and gate means coupled to said reference signal and to said test pulses for producing said warning signal upon the loss of said variable frequency source signal.

Claim 9

The missing pulse detector of claim 6, wherein said bistable means and gate means comprise: a first device having an output with a first state triggered by the reference signal and with a second state triggered by the test signal; a NAND gate for producing an output signal unless the reference signal and the output of the first device are in a selected state; a second device having an output with a first state triggered by the output signal of said NAND gate and with a second state triggered by the test signal; and an AND gate for producing said warning signal when the reference signal and the output of the second device are in a selected state.