Voltage measuring apparatus

专利名称：Voltage measuring apparatus发明人：BOWES ROBERT COLIN,GILL JOHN C.申请号：US72088458申请日：19580312公开号：US3052845A公开日：19620904

摘要：875,143. Electric selective signalling systems. NATIONAL RESEARCH

DEVELOPMENT CORPORATION. March 11, 1958 [March 14, 1957], No. 8446/57. Class 40(1). Apparatus for measuring voltage comprises a comparison circuit receiving an inputand a reference voltage; means for changing the latter by progressively smaller steps inbinary sequence wherein each of a plurality of connecting means is operable to. connector disconnect a different step of reference voltage and a pulse signal source appliespulse signals to inputs of the connecting means which ensure their operation to connectthe steps in binary sequence; the arrangement being such that each pulse signal is fed toa gated path as well as to its 'given connecting means, the gated path gives controlledaccess to the preceding connecting means in the binary sequence to disconnect thecorresponding voltage step; and the comparison circuit controls the gates of the pathsso that upon the occurrence of a pulse signal a voltage step connected in response tothe succeeding pulse signal remains connected or is disconnected according to the resultof a comparison between the input and reference voltages with the voltage step

connected; while means are associated with the voltage sources for indicating which stepsof reference voltage remain connected after completion of the binary sequence, wherebythe magnitude of the input voltage is indicated in terms of a binary number. In Fig. 1 an

input voltage is applied to fixed contact 2 of a chopper whose fixed contact 3 is fed froma binary reference voltage source and whose moving contact operated by drive 9 fromcontrol multivibrator 10 feeds comparison differentiating circuit 6 alternately with inputand reference voltages to produce negative or positive pulses as the input is greater orless than the reference voltage, which energize limiting amplifier 7 (Fig. 3, not shown) totrigger the overshoot inhibited generator 8 (Fig. 2, not shown) on positive pulses togenerate long gating pulses. Multivibrator 10 drives pulse separator 12 through delaycircuit 11 to produce for every train of 11 delayed multivibrator pulses a first outputpulse at PS1, a second at PS2, a third at PS3, up to an eleventh at PS11 of which outputsPS1 to PS10 trigger respective bi-stable circuits BS1 to BS10 to sequentially operaterelays A to J whose contacts A1 to J1 connect graduated resistors 13 to 22 respectively inseries with a stabilized voltage source 23 to fixed contact 3, which is earthed over resistorFBR, so that a binary coded voltage is applied to the contact in successive incrementseach of which is half the magnitude of the preceding increment. In operation a start signalon terminal 24 trips multivibrator 10 and clears all the bi-stable circuits BS1-BS10 torelease relays A to J so that no reference voltage is developed and source 23 is earthedover resistors 13 to 22. The first operative edge of the multivibrator output triggers drive9 to change over contact 5 from 3 to 2, and after a delay a pulse at PS1 operates bi-stable circuit BS1 and relay A to connect to contact 3 a reference voltage (1) determinedby resistance 13. The next operative edge of the multivibrator output triggers chopperdrive 9 to change over contact 5 from 2 to 3. The third operative edge triggers chopperdrive 9 to change over contact 5 from 3 to 2, the input and reference voltages arecompared and a positive or negative pulse is supplied by differentiating circuit 6 throughamplifier 7 to gate pulse generator 8 which is inoperative when input is greater thanreference voltage, but operates when reference is greater than input voltage to openbiased diode gates 26 (Fig. 2, not shown) between the respective outputs PS2 to PS11 ofthe pulse separator 12 and the bi-stable circuits BS1 to BS10 to route separated pulsesto the respective bi-stable transistor multivibrator circuits BS1 to BS10 (Fig. 2, not shown)

corresponding to the preceding output PS1 to PS10. The third operative edge alsoproduces with delay a pulse at output PS2 which operates bi-stable circuit BS2 and relayB. Since gate 26 is closed, the preceding bistable circuit BS1 is not pulsed by PS2, andrelay A remains operative. Resistor 14 is connected over B to contact 3 to add a binaryincrement (¢) of reference voltage determined by resistor 14. On the fourth operativeedge of the multivibrator output, chopper drive 9 changes over contact 5 from 2 to 3, andon the fifth operative edge, contact 5 changes back so that a further comparison is madebetween reference and input voltages. If the former is now assumed to be greater thanthe latter, gate pulse generator 8 is positively triggered to apply a long pulse to gates26, which open and in particular connect the next pulse separator PS3 output to thepreceding bi-stable circuit BS2. Thus when a delayed pulse corresponding to the fifthoperative edge appears at output PS3, gates 26 are open and bi-stable circuit BS3 ispulsed to operate relay C, while bistable circuit BS2 is also pulsed to release relay B. Theincrement of reference voltage added on operation of relay B is removed and operationof relay C connects through C 1 a resistor 15 through which a smaller (“) binary

increment of voltage is added. These comparisons between input and reference voltagesto determine whether or not an added binary increment should remain continues assuccessive oddnumbered operative edges are generated by multivibrator 10 originatesuccessive pulses in outputs PS4 to PS11 of pulse separator 12 each of which add a binaryincrement and initiate decision as to whether the preceding increment should remain orbe removed. The magnitude of the input voltage is determined in successive

approximations as successive digits of a binary coded number represented by the recordcontacts A2 to J2 of relays A to J. The start signal applied over terminal 24 initiates thepulse separator 12 and multivibrator 10 to generate 11 pulses or 22 operative edges sothat 11 output pulses corresponding to odd-numbered edges are produced by

generator 12 in sequence of one per output PS1 to 11, so that on each cycle of operation,the input voltage is measured to 10 binary places. A time serial output may be obtained

from the positively and negatively pulsed output of amplifier 7 according as the addedincrement of reference voltage is to be added or removed by means controlled bymultivibrator 10 for selecting pulses corresponding only to comparisons made on the3rd, 5th, 7th, &c., operative edges of the multivibrator pulses.

申请人：NATIONAL RESEARCH DEVELOPMENT CORPORATION

更多信息请下载全文后查看