Патент USA US2405073код для вставки
R. E. TROLL 2,405,073 PHASE COMPARATOR Filed Oct. 28, 1943 Inventor‘ : Roy E. Troell, iVa/wzéfjm/w by His ttorney. Patented July 30, 1946 2,405,673 UNITED STATES PATENT OFFICE 2,405,073 PHASE COIWPARATOR Roy E. Troell, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application October 28, 1943, Serial No. 507,952 3 Claims. (Cl. 172—-245) 1 2 The present; invention relates to a phase com parator adapted for use at high frequencies. The object of my invention is to provide a phase comparator in which the input and meas uring circuits can be grounded without impair ing the accuracy and in which the need for a 90 ‘The phase comparison circuit, because of the symmetry in the input and measuring circuits which permits grounding along the axis of sym degree phase shifting network is eliminated. The novel features which I believe to be char acteristic of my invention are set forth with par metry, is suitable for use at high frequencies; e. g. 30 me. The parallel tuned bridge circuits are an improvement over separate 90 degree phase shift ing networks. If there is any stray capacity. such as that resulting from the leads or the diodes I1, l8, it can be neutralized by inductances 22. 23 ticularity in the appended claims. My invention 10 connected across the terminals l, 2 and induct ances 24, 25 connected between ground and the itself, however, both as to its organization and method of operation, together with further ob terminals l4, l6. While I have shown particular embodiments of jects and advantages thereof, may best be un derstood by reference to the following descrip my invention, it will be understood that many tion taken in connection with the accompanying 16 modi?cations may be made without departing drawing in which the single ?gure is a diagram of from the spirit thereof, and I contemplate by the a phase comparator embodying my invention. appended claims to cover any such modi?cations Referring to the drawing there is shown a phase comparator having pairs of input terminals as fall within the true spirit and scope of my invention. I and 2 to which are applied the voltages E1 sin 20 What I claim as new and desire to secure by wt and E2 sin (wt+0) to be compared in phase. Letters Patent of the United States is: One of each pair of terminals is grounded and 1. In a phase comparator, grounded input cir across the respective pairs of terminals are con cuits for the voltages to be compared in phase, nected a bridge circuit 3., 4 each of which com lagging and leading phase shifting networks prises equal resistances 5, 6 and inductances ‘I 25 across each of the input circuits. center tapped and condensers 8 having reactances at the fre decoupling impedances respectively cross con quency of the voltages to be compared equal in necting the lagging phase shift voltage of one and magnitude to the resistances. At the terminals I the other input circuit to the leading phase shiit and 2 the bridge circuits are parallel tuned at the voltage of said other and one input circuit. square operating frequency. Because the resistances are 30 law detectors for the voltages at said center taps, equal to the inductive and capacitive reactances, and means for subtracting the detected voltages. the voltages at the intermediate bridge terminals 2. In a phase comparator, input circuits for 9, Ill and ll, [2 respectively lag and lead the the voltage to be compared each connected to voltages applied to the terminals I and 2 by 45 diametral terminals of a parallel tuned bridge degrees. By means of decoupling resistances l3 35 circuit, intermediate terminals of said bridge cir the lagging voltage from terminal 9 is added to cuits having potentials leading and lagging with the leading voltage from terminal l2 producing respect to the input voltages, center tapped de a resultant voltage at the center tap l4 propor coupling impedances respectively cross connect tional to E1 sin (wt—45°)+Ez sin (wt+6'+45°). ing said leading potential of one and the other Similarly by decoupling resistances I5 the lead 40 of said bridge circuits with said lagging potential ing voltage from terminal I0 is added to the of said other and one bridge circuit, square law lagging voltage from terminal II to produce at detectors for the resultant voltages at said cen the center tap i B a resultant voltage proportional ter taps, and means for subtracting the de to E1 sin (wt+45°)+E2 sin (wt+0—45°). The voltages at terminals l4 and [6 are respectively 45 tected voltages. 3. In a phase comparator, input circuits for fed through square law detectors, such as diodes the voltages to be vcompared each connected to l1 and i3. causing the charging of grounded con diametral terminals of a parallel tuned bridge densers l9 and 2!! in accordance with the squares circuit, said bridge circuits having arms of equal of the resultant voltages. Because the diodes are connected in opposite polarity, the condensers are 50 impedances consisting respectively of resistances and reactances whereby at the intermediate charged to voltages of opposite polarity and the bridge terminals the input voltages are shifted addition of the condenser voltages at terminal 24 in phase 45° leading and lagging, means for re is in effect a subtraction which results in a D.-C. spectively adding the leading voltage of one and voltage above ground proportional to E1 E2 sin 0 the other bridge circuit to the lagging voltage of at terminal 2!. There are also A.-C. voltages which do not affect a D.-C. voltmeter. The volt said other and one bridge circuit to obtain re age at terminal 2|, when measured by a D.-C. voltmeter. will accordingly change sign as the rel sultant voltages, square law detectors for the re sultant voltages, and means for subtracting the ative phase displacement (0) goes from positive detected voltages. to negative so the operator can tell whether a voltage is lagging or leading. ROY E. TROELL.