US2714658A - Decoder - Google Patents

Description

SOURCE INVEN TOR.

ALEXANDER GREENFELD United States Patent O DECUDER Alexander Greenfield, Detroit, Mich., assignor to Bendix Aviation Corporation, Detroit, Mich., a corporation of Delaware Application November 2, 1950, Serial No. 193,735 Claims. (Cl. Z50- 27) This invention relates to an electrical system for determining the time intervals between successive pulses and more particularly to a system for producing signals recurring at predetermined intervals between successive pairs of adjacent pulses.

In the present electronic applications, a series of pulses is often formed to provide information on the basis of the separation between pulses. The pulses are transmitted to a distant station where they are decoded, recorded and analyzed. The systems now in use for decoding the time periods between successive pulses do not convert the periods into a form which can be easily recorded and analyzed. Furthermore, the circuits are relatively complex and bulky.

This invention provides a system which produces signals recurring at predetermined intervals during each period defined by adjacent pulses. The signals are in a positive form so that they can be easily counted to determine each time period. The system requires a minimum number of parts, including vacuum tubes, and provides a maximum amount of stability and reliability.

An object of this invention is to provide a system for determining the period of time between adjacent pulses.

Another object is to provide a system of the above character for converting the period of time between successive pulses into a positive form which can be stored and subsequently recorded and analyzed.

A further object is to provide a system of the above character for producing positive pips at predetermined intervals during each period dened by adjacent pulses.

Still another object is to provide a system of the above character giving a maximum amount of eiiciency with a minimum number of parts.

Other objects and advantages will be apparent from a detailed description of the invention and from the appended drawings and claims.

In the drawings:

Figure 1 is a block diagram of a system constituting one embodiment of the invention; and

Figure 2 illustrates wave forms of voltages at strategic points in the system shown in Figure l.

In one embodiment of the invention, negative triggering signals are introduced from a source 10 through a coupling capacitance 12 to the grids of the left and right tubes in a bistable multivibrator 14 and to the grids of the right tubes in bistable multivibrators 16 and 18. Each multivibrator has a pair of capacitances which connect the grid of one tube to the plate of the other tube in the multivibrator. Thus, capacitances 20 and 22, capacitances 24 and 26 and capacitances 28 and 30 are provided in the multivibrators 14, 16 and 18, respectively.

The plate of the left tube in the multivibrator 14 is connected to the grids of the two tubes in a biased multivibrator 32 and to the grid of the left tube in the multivibrator 16. The plate of the right tube in the multivibrator 14 is connected to the control grid of a pentode in a gating circuit 34.

The plate of the left tube in the multivibrator 16 is connected to the grids of the two tubes in a biased multivibrator 36, as well as to the grid of the left tube in the multivibrator 18. The plate of the right tube in the multivibrator 16 is connected through a coupling capacitance 38 to the control grid of a pentode in a gating circuit 40, similar to the gating circuit 34.

A connection is made between the plate of the left tube in the multivibrator 18 and the control grid of a pentode in a gating circuit 42, similar to the gating circuits 34 and 40. The plate of the right tube in the multivibrator 18 is connected to the control grid of the pentode in the gating circuit 40.

The plate of the left tube in the biased multivibrator 32 is connected to the suppressor grid of the pentode in the gating circuit 42, as well as to the suppressor grid of the pentode in the gating circuit 4I). from the gating circuits 40 and 42 are taken from leads 44 and 46, respectively. In like manner, a connection is made between the plate of the left tube in the biased multivibrator 36 and the suppressor grid of the pentode in the gating circuit 34, and the output from the gating circuit 34 is taken from a lead 48.

The left tubes of the multivibrators 14, 16 and 18 are normally conductive.

grid of the right tube in the multivibrator, causing the right tube to conduct. The increased voltage on the plate of the left tube in the multivibrator 14 continues until a second negative triggering signal, indicated at 52, is introduced to the grids of the two tubes` in the multivibrator. The right tube then becomes cut off, and the left tube again starts to conduct through the action of the capacitance 20.

Since the left tube of the multivibrator 14 it cut oi between the triggering signals 50 and 52, a positive pulse, indicated at 54, is produced on its plate during this period. A positive pulse, indicated at 56, is also produced on the plate of the left tube in the multivibrator 14 during the period between third and fourth negative triggering signals 58 and 60, and a complementary positive pulse, indicated at 62, is formed on the plate of the right tube during the period between the signals 52 and 58.

The voltage on the grid of the left tube in the multivibrator 16 follows the voltage on the plate of the left tube in the multivibrator 14 and becomes negative upon the introduction of the triggering signal 52 to the multivibrator 14. The left tube in the multivibrator 16 is then cut oif, and a positive pulse, illustrated at 64 in Figure 2, is produced on its plate. This pulse is terminated upon the introduction of the triggering signal 58 to the grid of the right tube in the multivibrator 16. Since a positive pulse appears on the plate of the left tube in the multivibrator 16 only during the period between the signals 52 and plates of the left and right tubes are complementary,

signals 50 and 52 and between the signals 58 and 60.

Ihnlike manner, the negative slope of the pulse 64, co-

off. The resultant positive pulse, indicated at 70, which is produced on the plate of the left tube in the multivibrator 18, continues until the triggering signal 60 is introduced to the grid of the right tube in the multivibrator 18. The right tube in the multivibrator 18 then becomes cut oit and the left tube again conducts. Thus, a single positive pulse appears on the plate of the right tube in the multivibrator 18 upon the introduction of the triggering signal 50 'and continues until the introduction of the triggering signal 58. This pulse is illustrated at 72 in Figure 2.

. In addition to .being introduced to the grid of the left tube in the multivibrator 16, the voltage on the plate of the left tube in the multivibrator 14 is introduced to the grids of the two tubes in the biased multivibrator 32. The left tube of the biased multivibrator 32 normally conducts, but upon the introduction of a positive signal to the grids of the two tubes in the multivibrator, the multivibrator becomes free running and the two tubes alternately conduct to produce oscillatory signals having a predetermined length, such as 30 microseconds. The positive signals produced in an oscillatory manner on the plate of the left tube in the biased multivibrator 32 are indicated at 74 in Figure 2. As previously explained, these oscillatory signals occur between the triggering signals 50 and 52 and between the signals 58 and 60. Similarly, oscillatory signals, indicated at 76, are produced on the plate of the left tube in the biased multivibrator' 36 during the period between the triggering signals 52 and 58. This results from the fact that the positive pulse 64 appearing on the plate of the left tube in the multivibrator 16 during the period between the signals 52 and 58 is introduced to the grids of the two tubes in the multivibrator 36.

The gating stages 40, 34 and 42 conduct when positive signals are simultaneously introduced from at least one ol the bistable multivibrators 14, 16 and 18 and one of the biased multivibrators 32 and 36. Thus, the gating circuit 40 passes the oscillatory signals from the biased multivibrator 32 only during the period between the triggering signals 50 and 52, since the positive signal on the plate of the right tube in the multivibrator 16 and the positive signal on the plate of the right tube in the multivibrator 18 coincide only during this period. The oscillatory signals from the gating circuit 40 are illustrated at 78 in Figure 2.

Similarly, during the period between the triggering signals 52 and 58, the positive pulse 62 on the control grid of the pentode in the gating circuit 34 coincides with the positive oscillatory signals 76 on the suppressor grid of the pentode. The gating circuit 34 conducts and channelizes the oscillatory signals into a separate output through the lead 48, as illustrated at 80 in Figure 2.

The gating circuit 42 conducts during the period between the triggering signals 58 and 60 as a result of the positive pulse 70 from the plate of the left tube in the multivibrator 18, and the positive oscillatory signals 74 from the plate of the left tube in the biased multivibrator 36; The positive oscillatory signals, indicated at 82, are channelized into a separate output through the lead 46.

The system disclosed above has several advantages. It provides a positive indication of the time periods between successive triggering signals by producing positive signals at predetermined intervals during each period. The time indication may be made as accurate as desired by reducing the time required to produce each oscillatory signal in the multivibrators 32 and 36. The oscillatory signals can be easily counted and can be easily stored for subsequent recordation and analysis to provide an efiicient and reliable time indication. Furthermore, the system passes the positive oscillatory signals between the different pairs of adjacent pulses into separate channels to facilitate the subsequent recordation and analysis. The system employs a minimum number of stages to provide the time indications. For example, only the two multivibrator stages 32 and 36 are required to produce oscillatory signals for three channels.

Although this invention has been disclosed and illustrated with reference to particular applications, the principles involved are susceptible of numerous other applications which will be apparent to persons skilled in the art. The invention is, therefore, to be limited only as indicated by the scope of the appended claims.

a particular one of the e particular output terminal of What is claimed is:

l. In combination, a pulse source for providing a plurality of pulses in a sequence, iirst, second and third bistable multivibrators each having a pair of input terminals and a pair of output terminals, both input terminals of the first multivibrator being connected to the pulse source, one of the input terminals of the second and third multivibrators being connected to the pulse source, the other input terminal of the second multivic'rator being connected to a particular one of the two output terminals of the first multivibrator, the other input terminal ot the third multivibrator being connected to two output terminals of the second multivibrator, a first oscillator connected to the particular output terminal of the first multivibrator and responsive to a particular state of equilibrium in the multivibrator to produce signals at particular intervals during the period between the first and second pulses from the source and during the period between the third and fourth pulses from the source, a second oscillator connected to the particular output terminal of the second multivibrator and responsive to a particular state of equilibrium in the multivibrator to produce signals at particular intervals during the period between the second and third pulses from the source, and first, second and third gating stages connected to a particular one of the oscillators and to a particular output terrninal of a particular multivibrator and responsive to a particular state of equilibrium in the multivibrator to pass in sequence the oscillatory pulses produced between the successive pairs of adjacent pulses in the sequence.

2. In combination, a pulse source for providing a plurality of' pulses in a sequence, first, second and third bistable multivibrators each having a pair of input terminals and a pair of output terminals, the input terminals of the first multivibrator being connected to the pulse source, one of the input terminals of the second and third multivibrators being connected to the pulse source, the other input terminal of the second multivibrator being connected to a particular one of the two output terminals of the first multivibrator, the other input terminal of the third multivibrator being connected to a particular one of the two output terminals of the second multivibrator, a iirst oscillator connected to the the first multivibrator and responsive to a particular state of equilibrium in the multivibrator to produce signals at particular intervals during the period between the first and second pulses from the source and during the period between the third and fourth pulses from the source, a second oscillator connected to the particular output terminal of the second multivibrator and responsive to a particular state of equilibrium in the multivibrator to produce signals at predetermined intervals during the period between the f; second and third pulses from the source, a first gating stage connected to particular output terminals in the second and third multivibrators and to the first oscillator to pass signals during the period between the first and second pulses from the source, a second gating stage connected to the other of the two output terminals in the first multivibrator and to the second oscillator to pass signals during the period between the second and third pulses from the source, and a third gating stage connected to a particular output terminal in the third multivibrator and to the first oscillator to pass signals during the period between the third and fourth pulses from the source.

3. In combination, a pulse source for providing a plurality of pulses in a sequence, a first bistable member connected to the pulse source to change from its original state of equilibrium and to return to its original state of equilibrium upon from the source, a second bistable member connected to the first bistable member and to thepulse source to change from its original state of equilibrium upon the return of the first bistable member to its original state of equithe introduction of alternate pulsesr libriurn and to return to its original state of equilibrium upon the introduction of the next pulse from the source, a third bistable member connected to the second bistable member and to the pulse source to change from its original state of equilibrium upon the return of the second bistable member to its `original state of equilibrium and to return to its original state of equlibrium upon the introduction of the next pulse from the source, a pair of oscillatory members connected to particular bistable members to produce signals at particular intervals during the period between each pair of successive pulses from the source, and first, second and third gating stages connected to particular oscillators and to particular output terminals of' particular multivibrators and responsive to particular states of equilibrium in the multivbrators to pass in sequence the oscillatory signals produced between the successive pairs of adjacent pulses in the sequence.

4. In combination, a pulse source for providing a plurality of pulses in a sequence, a first bistable member connected to the pulse source to change from its first state of equilibrium to its second state of equilibrium and to return to its first state of equilibrium upon the introduction of alternate pulses from the source, a second vbistable member connected to the first bistable member `and to the pulse source to change from its first state of equilibrium to its second state of equilibrium upon the return of the first bistable member to its first state of equilibrium and to return to its first state of equilibrium upon the introduction of the next pulse from the source, a third bistable member connected to the second bistable member and to the pulse source to change from its first state of equilibrium to its second state of equilibrium upon the return of the second bistable member to its first state of equilibrium and to return to its first state of equilibrium upon the introduction of the next pulse from the source, a first oscillatory member connected to the rst bistable member to produce signals at particular intervals during the operation of the bistable member in its second state of equilibrium, a second oscillatory member connected to the second bistable member to produce signals at particular intervals during the operation of the bistable member in its second state of equilibrium, a first gating member connected to the second and third bistable members and to the first oscillatory member to pass oscillatory signals only during the period between the first and second pulses from the source, a second gating member connected to the first bistable member and to the second oscillatory member to pass oscillatory signals only during the period between the second and third pulses from the source, and a third gating member connected to the third bistable member and the first oscillatory member to pass signals only during the period between the third and fourth pulses from the source.

5. In combination, means for providing a plurality of pulses in a sequence, a plurality of pulse forming stages connected to the pulse providing means for producing between each successive pair of adjacent pulses in the sequence a pulse having a width proportional to the time period between the pair of adjacent pulses, a plurality of timing stages connected to the pulse forming stages for producing signals at particular intervals during the production of each pulse by the pulse forming stages, and gating means connected to the pulse forming stages and the timing stages to separate the timing signals produced during the production of each pulse by the pulse forming stages.

6. In combination, a triggering source for providing a plurality of pulses in a sequence, a plurality of stages connected to the triggering source in cascade relationship to one another for becoming actuated in succession between successive pairs of adjacent pulses in the sequence, a plurality of timing stages connected to the first mentioned stages to produce a number of signals at particular intervals during the activation of each of the first' mem tioned stages, and a plurality of gating stages connected to at least one of the first mentioned stages and to one of the timing stages to pass in sequential pattern the signals formed by the timing stages during the activation of the first mentioned stages.

7. In combination, a pulse source for providing a plurality of pulses in a sequence, first, second and third triggering stages connected to the pulse source to become activated in sequence during the periods between successive pairs of adjacent pulses in the sequence, first and second oscillatory stages connected to the triggering stages to produce signals at particular intervals during the activation period of each triggering stage, and rst, second and third gating stages each of the gating stages being connected to particular triggering and oscillatory stages to provide a separate output for the sequential passage of oscillatory signals produced during the activation period of each triggering stage.

8. In combination, a pulse source for providing a plurality of pulses in a sequence, first, second and third triggering stages arranged in cascade relationship and connected to the pulse source for becoming activated in succession during the periods between successive pairs of adjacent pulses in the sequence, first and second oscillatory stages connected to the first and second triggering stages respectively for activation alternately by pulses from the rst and second triggering stages to produce signals at substantially constant intervals during the activation periods of the oscillatory stages, a first gating stage con nected to the second and third triggering stages and to the rst oscillatory stage to pass the signals from the oscillatory stage during the simultaneous activation of the triggering stages, and second and third gating stages connected to the second and first oscillatory stages, respectively, and to the first and third triggering stages, respectively, to separate the signals from the second and first oscillatory stages during the activation of the first and third triggering stages, respectively.

9. In combination, a pulse source for providing a plurality of pulses in a sequence, first, second and third triggering stages arranged in cascade relationship and connected to the pulse source to become successively activated during the periods between successive pairs of adjacent pulses in the sequence, the first triggering stage being connected to the pulse source for activation during the period between the first and second pulses in the sequence and during the period between the third and fourth pulses in the sequence, first and second oscillatory stages connected to the first and second triggering stages, respectively, to provide signals recurring at particular intervals during the activation of the associated triggering stage, and first, second and third gating stages connected to particular triggering and oscillatory stages to pass sequentially through the first, second and. third gating stages the recurrent signals produced during the activation of the first, second and third triggering stages, respectively.

10. In combination, a pulse source for providing a plurality of pulses in a sequence, a first triggering stage connected to the source for activation during the period between the first and second pulses in the sequence and during the period between the third and fourth pulses in the sequence, second and third triggering stages connected to the pulse source for activation during the periods between the second and third pulses and between the third and fourth pulses in the sequence, respectively, a rst oscillatory stage connected to the first triggering stage to provide signals recurring at particular intervals during the activation periods of the first triggering stage, a second oscillatory stage connected to the second triggering stage to provide signals recurring at predetermined intervals during the activation period of the second triggering stage, and first, second and third gating stages each connected to at least one of the triggering stages and one of the oscillatory stages to pass sequentially through the first, second and third gating stages the recurrent signals produced by the oscillatory stages during the activation of the rst, second and third triggering stages, respectively.

2,272,070 Reeves Feb. 3, 1942 8 Meachem Nov. 1, 1945 Grosdot July 16, 1946 Sallach June 15, 1948 Crost June 29, 1948 Cleeton July 6, 1948 Atwood et al. Oct. 10, 1950 Melhose Feb. 13, 1951 Trevor Feb. 27, 1951

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