MEANS FOR INHIBITING FLUTTER IN A NUMERICAL DISPLAY

• US 3,621,391 A
• Filed: 08/21/1969
• Issued: 11/16/1971
• Est. Priority Date: 08/21/1969
• Status: Expired due to Term

• Current Assignee: David E. Miller
• Original Assignee: David E. Miller
• Inventors: David, E. Miller
• Primary Examiner(s): Rudolph V. Rolinec
• Assistant Examiner(s): Ernest F. Karlsen
• Application Number:
  US04/852,050
• Time in Patent Office: 817 Days
• Field of Search: 324/99,120,99D 340/324,347A-347D 235/92(65)
• US Class Current: 324/99.00D
• CPC Class Codes: G01R 17/00 Measuring arrangements involving comparison with a reference value, e.g. bridge
• CPC Class Codes: H03M 1/60 with intermediate conversion to frequency of pulses

Abstract

Rapid oscillation between consecutive numbers displayed by a numerical display device is prevented by comparing an incoming digitally coded signal with one representing the numeral currently registered by the device. If the incoming signal corresponds to a numeral consecutive to the one being displayed, the system inhibits the registration of the new signal by the device. At predetermined intervals the comparison system is bypassed and the device is '"'"''"'"''"'"''"'"'updated'"'"''"'"''"'"''"'"' by allowing registration of new signals, regardless of their relationship to prior signals.

Claims

1. A numerical display system for visually displaying numerals indicative of a signal which is frequency modulated in response to a parameter to be measured, comprising:

a. means for sensing the frequency modulated signal at first periodic intervals;

b. means for converting each sensed frequency modulated signal into a corresponding binary signal;

c. a display device;

d. means for transmitting binary signals to said display device for effecting a numerical display indicative of a sensed frequency modulated signal;

e. means for preventing flutter of displayed numerals by inhibiting single digit changes in said binary signals from effecting said numerical display including, means for comparing one of the bits of each succeeding binary signal corresponding to later sensed frequency modulated signals with a corresponding bit of the preceding binary signal to inhibit transmission of succeeding binary signals which have single digit changes, said comparing means producing an inhibiting signal for inhibiting transmission of said succeeding binary Signals to said display device by said transmitting means when the polarities of successive signals have a first predetermined relationship and producing an enabling signal for effecting transmission of succeeding binary signals to said display device by said transmitting means when the polarities of said signals have a second predetermined relationship;

f. means for coupling said inhibiting and enabling signals from said comparing means to said transmitting means to control transmission of said binary signals to said display device;

g. updating means for effecting transmission of binary signals to said display device at second periodic intervals, regardless of the relationship of said successive signals.

2. The numerical display system of claim 1 wherein said comparing means comprises:

a. a first comparison gate;

b. means for periodically producing signals at a predetermined rate;

c. a flip-flop having an input and an output, said input being coupled to said signal-producing means; and

d. a second comparison gate for receiving signals from said first comparison gate and said flip-flop output and producing an output signal upon receiving said signals simultaneously.

3. The numerical display system of claim 1, wherein said updating means comprises:

a. means for periodically producing signals at a predetermined rate;

b. a flip-flop;

c. means for actuating said flip-flop upon sensing a predetermined number of said periodically produced signals;

d. comparison gate for receiving the output signal instituted by the actuation of said flip-flop and producing a latch signal in response thereto; and

e. means for resetting said flip-flop means and said actuating means upon the occurrence of said latch signal.

4. Flutter eliminating means as recited in claim 3 wherein said comparator means comprises:

a. a first compArison gate for producing a first output signal upon detection of a predetermined relationship between said first digital signal and said second digital signal; and

b. a second comparison gate for producing a second output signal upon detection of both said first output signal and an output signal from a periodically actuated signal source.

5. Flutter eliminating means as recited in claim 3 wherein said updating means produces an output signal after a predetermined number of signal comparing periods have occurred and is reset upon occurrence of said second output signal produced by said second comparison gate.

6. The numerical display system according to claim 1 including a register means for registering and storing the binary signals, said means having its input coupled to said converting means and its output to said display device, means coupling the input and output of said storage means to said comparing means for comparing corresponding bits of successive binary signals and producing said inhibiting and enabling signals, and means coupling said inhibiting and enabling signals from said comparing means to said storage means to control transmission of succeeding binary signals to said display device.