US2042831A - Receiving system - Google Patents

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US2042831A
US2042831A US727931A US72793134A US2042831A US 2042831 A US2042831 A US 2042831A US 727931 A US727931 A US 727931A US 72793134 A US72793134 A US 72793134A US 2042831 A US2042831 A US 2042831A
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frequency
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Murray G Crosby
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RCA Corp
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/08Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
    • H04B7/0837Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using pre-detection combining
    • H04B7/084Equal gain combining, only phase adjustments
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/08Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
    • H04B7/0837Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using pre-detection combining
    • H04B7/0842Weighted combining
    • H04B7/086Weighted combining using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming

Description

June 2, 1936. M. G. CROSBY RECEIVING SYSTEM Filed May 28, 1934 5 Sheets-Sheet l June 2, 1936. M. .G. cRbsBY 2,042,831

RECEIVING SYSTEM Filed May 28, 1934 5 Sheets-Sheet 2 3: a: I'M- 5E 91* INVENTOR f MURRAY 6. CROSBY ATTORN EY June 2, 1936. G CROSBY 2,042,831

RECEIVING SYSTEM Filed May 28, 1934 5 Sheets-Sheet 3 /KZW ATTORNEY jAAAll I'I'I Allll IIVII m QQ Ba 71 we; 56 Q I T MN wv v 37 a E w Q\ w N June 2, 19 36. M. G. CROSBY RECEIVING SYSTEM Filed May 28, 1934 5 Sheets-Sheet 4 ATTORNEY June 2, 1936. M e. CROSBY RECEIVING SYSTEM Filed May 28, 1934 5 Sheets-Sheet 5 Patented June 2, 1936 iii? 'i'A'i'S A'EENT FFlE RECEIVING SYSTEM Delaware Application May 28, 1934, Serial No. 727,931

17 Claims.

My present invention relates to a radio receiving system and has as its principal object the provision of a system wherein energy received from the antennae of a diversity array is combined in phase at all times.

A further and more specific object is to provide a system wherein the phase relation of currents derived from a diversity antenna system are maintained at a constant value so that currents derived from the antennae may be combined as though the phase of each antenna remained constant.

More fully, in the prior art of diversity reception there are two well known methods of combining the energies received from antennas having difierent fading characteristics. The first is rectifying the antennae energies and then combining the rectified energies; and the second is by means of an automatic volume control arrangement which automatically shuts off the amplifiers from all the antennas but the one having the strongest signal.

The first of these two systems of combination, namely, the combination of the rectified energies, is limited mostly to CW telegraphy circuits where the rate of modulation is not too high. Under certain atmospheric conditions and upon certain radiation frequencies (those in the vicinity of 20 megacycles and higher) direct combination of the rectified outputs of voice and music modulation feasible; however, the tendency is toward the second method of combination for these types of modulation. In fact, at the present timepractically all the voice and music diversity systems utilize the automatic volume control antenna choosing system.

Thus, prior diversity systems have combined the energies from the antennas by the addition of rectified outputs or by a choosing device whereby only a single antenna was made operative at one time. Hence, the antennas do not combine to improve directivity as would be the case if the radio or intermediate frequency energies were combined as they are in a broadside array. Such a combination of antennas giving a diversity ciiect has been impossible due to the fact that the phase or" the energies from the various antennas does not remain constant, at the value which the spacing and combination circuits determine, but vary relatively with fading. Consequently, a combination which might be effective at one instance of time might be ineffective at another as the fading progressed.

In the invention herein described means are provided for combining the R. F. or I. F. energies in a diversity system so that the system, in-

stead of having a directivity equivalent to that of a single antenna, has a directivity equivalent to a combination of all of the antennas. The

phases of the energies from each antenna are automatically controlled so that the phase of combination is always proper. Hence, a superdirective system is obtained which has all the advantages of the prior diversity systems.

A further advantage of the system herein described is that it may be utilized to effect a directive system which automatically changes its directivity in accordance with the changes in the bearing of the signal. Thus, as the signal comes in from different directions the antenna system auto- .2 Figures 1, 1a, 2, 3, 4 and 5 show schematic diagrams of various modifications of the fundamental idea. That is, Figure 1 shows an arrangement whereby the two antennae are held in phase by means of a motor operated phase shifter. Figure '10. gives an auxiliary combining arrangement to be used on the circuits of Figures 1, 2, 3 and 5. Figure 2 portrays a method of phasing whereby the frequency of one of the high frequency oscillators is varied to maintain phase synchronism of the two signals. Figure 3 shows a three receiver diversity system wherein the various signal I. F. energies are held in phase with an I. F. os-

the differential detector energy to vary the frequency of the common second I. F. oscillator. Figure 6 and the vector diagrams of Figures 7, 8, 9 and 10 are used in the explanation of the operation of the differential detectors.

In Figure 1 the two heterodyne receivers 2, 3

All

cillator, with a filtered and limited carrier, or

phase'shifting unit in the dotted line enclosure,

The energy from I. F. amplifier 5 is fed via Transformer l6 feeds 0!). line 15 to transformer i6.

coupling tubes I? and i8 having tuned circuits,

I9 and 2:; in their plate circuits. The tunings of 19 and-2B are adjusted so that their Voltages, in-

duced in coupling coil 2|, are 98 degrees out of phase, thus eflecting a phase shifter.

Coil 2|, which feeds transformer 1, is mounted on shaft 22 in bearing23. on the other end of shaft 22 is a friction drive wheel '24 circularly slotted so that flexible drive shaft 3!, driven by motor 25, rotates wheel 24 in a forward direction when drive shaft 35 engages one side of the slot, and ma reverse direction on the other side of the slot. (For a more complete description of this type of drive see D. R. Goddard applicationSerial Number 11,915, filed March 20, 1935.)

Rectified I. F. energy from detectors 8' and 9 operate solenoids 2i and 28 to move armature 25. Arm 25 is pivoted at one end and is provided with a forked bearing at the other end for engament with the shaft 3! so as to reversibly operate a clutch mechanism associated'there- -With.

An unbalance of currents in solenoids 21 and 28 causes armature 25 to shift shaft St to the forward or reverse engagement with wheel 24..

in general of my present invention, obtains its controlling energy from the differential detectors such as 8 and 9 of Figure 1. These differential detectors are fed cophasally by one of the signal or signal intermediate frequencies and antiphasally by the other. As long as the two signals are 90 degrees out of phase the plate currents of the detectors 8 and 9 are balanced and no differential voltage is passed on to operate the controlling circuits. As soon as the relative phase of the two signals deviates from 90 degrees, the detector plate currents are unbalanced and a differential voltage operates the controlling circuits to correct the phase relation to 90 degrees.

More specifically, and referring to the differential detector diagram of Figure 6 the two signal I. F.s are fed in at S1 and S2 to transformers 6 and 1 respectively. Figures '7 and 8 show how the voltages from transformers 8 and I combine when the two signals are 90 degrees out of p se. n, bu, T17 d A, (B7) Ru represent the vectors for tubes 8 and 9 respectively. Voltage 1) is supplied from transformer l and voltage a from transformer 6 to form the resultant r to be fed to tube 8. Voltage B is supplied from transformer I and voltage A from transformer 6 to form resultant R to be fed to tube 9. Thus, when the two signals are 90 degrees out of phase the resultants R and r are equal and the detected outputs across resistors or equal impedances 8x and 9x would cancel to form zero voltage between leads B and B Figures 9 and 10 show the vector relations when one signal has shifted in phase so that the two signals are no longer 90 degrees out of phase. The resultant r fed to tube 8 is greater than the r R fed to tube 9. Consequently, the drops across resistors 8X and 9x will no longer balance and a voltage will be applied to leads B and. 5 When the phase is shifted in the opposite direction this differential voltage is reversed. Consequently, a voltage is produced having a magnitude and direction dependent upon the relative phases of the two signals.

Referring again to Fig. l, the operation of my invention as therein shown will be fairly well understood from the foregoing description. When the signals from the two antennae l and i deviate from a 90 phase relationship the unbalance resulting in the differential detectors 8 and 9 becomes effective in controlling one of the clutch solenoids 21 or 28 of the phase shifter so as to cause the motor 26 to rotate the coil 21 in the proper direction and through a suitable angle to restore the desired 90 relationship between the currents in coils s1 and s2. When the balance has been restored, the armature 25 is returned to its neutral position, thus disengaging its associated clutch mechanism.

In some cases it may be found desirable to have the antennae combined at a phase other than 90 degrees. To do so the outputs of I. F. ampliher 5 and coil 2| should be fed to couplin: tubes, their relative phase adjusted, combined, and detected. Such a combining arrangement is shown in Figure 1a. The two signals (phase controlled to 90 degrees) would be taken from leads gxy, Hixy and llx lzxy of Figure l The signals in these leads would then be adjusted to the desired phase of combination by phase shifter lx and combined through combining tubes ix and 5X in transformer Ex Detector Ixy detects the combined signals for utilization in jack 8 The system illustrated in Figure 1 may be used for direction finding by, for example, associating with shaft 22 a pointer P movable angularly with shaft 22, and a relatively stationary scale S. The antennae l and l for this purpose should be spaced or be two directional arrays of antennas.

'With such an arrangement, the pointer P would indicate on the scale the phase relation between the waves picked up upon l with respect to I. By having previously calibrated the scale when in harbor, say, on known directions of several known transmitting stations, then, when at sea, deviation from the calibration would give deviation from the course.

If desired, by means of the Selsyn motors SMI, whose armature coincides with shaft 22, and SM2 operating steering mechanism, guidance or steering of a ship may be made automatic.

Incidentally, the system of Figure -1 is intended for operation with amplitude modulated waves. For reception of phase and frequency modulated waves, leads fixy to Zry inclusive should be connected to suitable phase or frequency modulation receivers, with, if desired, a suitable retardation circuit in either leads xy, lQxy OI Hxy, lzxy. V

In Figure 2, separate H. F. oscillators X6 and X4 are employed for the two superheterodyne receivers. The combined and detected energy is taken from detectors X8 and X9 via transformer Xl3. Switch XIZ adjusts for proper phase of audio frequency combination; the nor- I are cophasal.

mal position of this switch would be for parallel combination of the two detector outputs. Oscillator X4 is held in the proper phase synchronism with Xe to hold the output of I. F. amplifiers X and X5 in phase quadrature by means of energy furnished from the resistors X and XM in the detector plate circuits. This differential voltage is applied to oscillator X4 which is an oscillator whose frequency is partly dependent upon its tuning and partly upon the control voltage applied to it. A complete description of oscillator X l and its frequency controlling circuit is given in my copending application, Serial Number 616,803, filed June 13, 1932.

In the operation of receiver of Figure 2 the two I. F.s are held in phase quadrature by applying the controlling energy to one of the H. F. oscillators. This controlling voltage varies the frequency of the H. F. oscillator to obtain the proper 90 degree phase relation of the two I. F.s. The outputs of X5 and X5 may also be fed through 1aldS xy, iflxy, Xy, izxy to the combining circuit of Figure 1a for other than 99 degree combination of the antennae as will be apparent from what has been said before.

Briefiy, for varying the frequency of the oscillator 285 within dotted rectangle X4 of Figure 2, the output of the differential detector is fed through conductors X55 to a coupling tube 282 having a plate coil 286 coupled to the tuned circuit 234 controlling the frequency of operation of the oscillator 23%. With a predetermined current flowing through tube 282, the inductance of circuit 23 will be a certain value causing a predetermined frequency of operation of the local oscillator 23%. With variations in voltage both of value and sign across conductors Xl5, the impedance, that is the impedance of tube 262 across coil 2% will vary, thereby changing the frequency of operation of the local oscillator 23% because of the change of effective inductance of tuned circuit 284.

The system of Figure 3 utilizes the same principle as the arrangement of Figure 2 except that the individual I. F. energies are held in phase with: (1) The combined I. F. energy (which would be portrayed if unit H! were a coupling tube fed through closed switch I?) (2) A locally supplied I. F. oscillator contained in unit M (in which case switch I? would be open); (3) The filtered and limited carrier (switch closed). With unit It acting as a coupling tube according to (1), line l8 may contain an artificial line or Wave filter to act as a retardation circuit to allow the reception of frequency modulation in the manner of the receivers described in my copending application, Serial Number 618,154, filed June 20, 1932. With unit l4 containing either the I. F. oscillator or carrier filter, a local carrier is available for the reception of phase and amplitude modulation. Automatic volume control unit 19 operates on coupling tube units l3a, 53b, and i3c, via lead 20, to maintain the volume of the combined energy constant.

Generally, in connection with Figure 3, differential detectors Ea, 8a, "5b, 8b, 7c, 80, act so that the outputs of coupling tubes l3a, |3b-, and |3c The combined cophasal output of lw, i311, |3c is fed to antiphasal transformer 2|, and the output of unit U5 is fed to cophasal transformer 22 of detectors 23, 24. Phase shifter 28 serves to adjust the currents fed to 22 and 2| so as to be of correct phase relationship for audio frequency detection.

The receiver of Figure 3 is an elaboration of the fundamental idea contained in the receiver of Figure 2 except that the signals are all held in phase quadrature with a standard instead of with each other. This standard, as before stated, may be an I. F. oscillator or the filtered and limited carrier; it may also be the combination of the signals. With this sort of an arrangement, since the signals would all be combined in phase quadrature with the standard,

they would be in phase with each other so that the combining circuit of Figure la would only be necessary for other than in phase combination. Referring in greater detail to the circuit of Figure 3, the standard (consisting of an I. F. oscillator, the filtered carrier, or the combined signals) is fed to the differential detectors via cophasal transformers 6a, 6b, and 6c. The three signals at I. F. are fed via antiphasal transformers 5a, 5b and 5c. The controlling energy from the differential detectors is utilized to automatic frequency control the H. F. oscillators to maintain the proper frequency and phase, for combination, of all of the I. F.s. The three I. F.s are passed through coupling tubes |3a, |3b and |3c to the automatic volume control detector l9 and to the audio detectors 23, 24. The

automatic Volume control may be made to regu- 9 late the volume of the total combined signal or the separate coupling tubes as shown in the diagram of Figure 3 or the individual radio frequency amplifiers in the manner of the antenna choosing diversity system as described in U. S. Patent 2,004,128, granted June 11, 1935 to H. 0. Peterson. For phase modulation and relatively increased carrier amplitude modulation reception, unit I4 would be an I. F. oscillator, or a carrier filter and limiter fed by closing switch H. For frequency modulation a phase retardation circuit whose output phase is linearly proportional to its input frequency would be inserted in line l8 and unit I4 would act as a coupling tube to couple the combined energy to the differential detectors as a standard, and to the audio detectors via line Hi.

When receiving amplitude modulated waves in the arrangement shown in Figure 3, unit It may be a local oscillator, in which case phase shifter 28 is adjusted so that either tube 23 or 24 is excited cophasally, in which case, too, the outputs of 23, 24 are switched by switch 25 in push-pull.

In the alternative, for amplitude modulated waves with unit M an oscillator, phase shifter 28 may be adjusted so that currents in 22 and 2| are 90 degrees apart and switch 25 thrown for parallel feed of the primaries of transformer 26.

The foregoing remarks concerning adjustment apply for reception of amplitude modulated Waves when unit I4 is made a carrier filter and limiter. However, when unit it is merely a coupling system whose output is the combined signal, only line l5 or only line l8 should feed detectors 23 and 24. Also, in either of the latter instances the primaries of transformer 26 should be in parallel.

When receiving frequency modulated Waves, assume unit It has an output equal to the combined signals. Shifter 28 should be adjusted for 90 degrees phase difference in currents in 2| and 22 and, moreover, a retardation circuit should be placed in line I8.

When utilizing the system of Figure 3 for reception of phase modulated waves, unit l4 should be operated only as a carrier filter or carrier oscillator. By means of phase shifter 28, the currents in 22 and El should be displaced degrees and the primaries of transformer 26, assumed to be wound in the same direction, should be connected in push-pull.

It should be noted that by using correction circuits, the frequency modulation adjustment may be used for phase modulation reception and that frequency modulation reception may be carried on with the phase modulation adjustment. Thus, by putting a circuit across 2'! whose output is inversely proportional to the input frequency, the system of Figure 3 adjusted for frequency modulation reception will operate to give true reproduction from received phase modulated waves.

By connecting a circuit to 21 whose output varies linearly with the applied input, the receiver will, with a phase modulation adjustment, faithfully reproduce the signal from received frequency modulated waves.

In the system of Figure 4, the triple detection superheterodyne receivers i, 2, 3, 4, 5, 6, 7 and I, 2, 3, i, 5, 6, i use a common high frequency oscillator i and separate I. F. oscillators 6 and 8'. Oscillator 5 is frequency controlled from the differential detectors 9 and I0 which are fed antiphasally by the intermediate frequency energy from one receiver and cophasally by that from the other receiver. This control may be done in a manner similar to that for oscillator X4 of Figure 2. Coupling tube units 1 and 'i separate the controlling energy and the energy combined for utilization in detectors I8 and I9. Phase shifter 25 adjusts the phase of combination of the two energies for u ilization. Automatic frequency control such as described in Figure 2 is applied Via line i to the high frequency oscillator 4. Unit I5 contains a crystal filter, limiter, and phase shifter for phase and amplitude modulation reception and an artificial line or wave filter for frequency modulation reception. The detection in this receiver incorporates the principles given in my copending application, Serial Number 616,803, filed June 13, 1932.

In operation the circuit of Figure 4 utilizes the same principle as the one of Figure 2 except that the second oscillator of a triple-detection superheterodyne is frequency controlled to maintain the proper phase synchronism. The circuit is shown with an automatic-frequency-control crystal-filter detecting circuit, but could be used on any other detecting arrangement for any type of modulation. Since the two signals are held in phase quadrature, the phase adjuster 25 is necessary for combinations at other than 90 degrees.

The system of Figure 4 is suitable for amplitude frequency and phase modulation reception, it being noted that for phase and amplitude modulation reception adjustments are made as prescribed for Figure 3. For frequency modulation reception, unit iii of Figure 4 should be a retardation circuit.

In the system of Figure 5, triple detection superheterodynes are utilized and the intermediate frequency energies are held in phase by inserting an artificial line or wave filter i in one I. F. circuit and applying the difierential voltages from detectors l8 and H to frequency control the common second I. F. oscillator 6.

The audio output is taken from transformer l5.

In the circuit of Figure 5 the phase adjustment is obtained by using the differential detector controlling energy to vary the frequency of the common second oscillator of the triple detection superheterodynes and inserting a retardation circuit 1 in one of the second I. F. circuits. Thus, as the second I. F. is varied, the phase of the I. F. through the retardation circult is changed relative to the one not through the retardation circuit and the phase adjustment is obtained. This retardation circuit could also be inserted in series with the leads from oscillator 6 to amplifier 5 so that the modulated signal would not have to pass through it.

The system of Figure 5 is suited for amplitude modulation reception. For phase and frequency modulation reception, the primaries of transformers 8 and 9 should be made to feed into suitable phase and frequency modulation re ceivers.

Although my present invention has been described in connection with a diversity receiving system, its use need not be limited to such an application. The fundamental idea gives a receiver which automatically corrects the phase relation between two receiver outputs. Consequently, as already shown, it may be used in a direction finder whereby the controlling energy operates a meter to indicate the bearing of the received. station and it may also be used as a radio control for mobile craft in which the controlling energy operates the steering apparatus so that the craft will be guided on a given bearing with relation to the received signal.

Also this system may be used for frequency diversity. For example, the circuits of Figures 1, 2 and 3 may be used to hold two signals of different radiation frequency in frequency and phase synchronism at I. F.

Moreover, although most of the circuits have been drawn to utilize only two antennae, it will readily be apparent that any number of antennae may be used by a continuation of the same ideas given herein.

Having thus described my invention, what I claim is:

1. The method of reducing fading of radio signals which includes making a plurality of signal energy collections, producing and maintaining a predetermined phase displacement in the energies collected, combining the phase displaced energies, detecting the combined phase displaced energies and translating the detected energies.

2. The method of reducing fading of radio signals which comprises making a plurality of signal energy collections, producing a predetermined phase displacement in the energies collected, combining the phase displaced energies, maintaining the phase displacement substantially constant before combination despite variations in phase of the received energies during their collections, detecting the combined energies, and translating the detected energies.

3. The method of receiving radio signals which comprises separately receiving said signals, combining the signals in pretermined phase displacement, detecting the combined signals, utilizing the voltage variations of the detected signals to maintain the predetermined phase displacement of the collected energies before combination and utilizing the detected combined energies for signal translation purposes.

4. The method of reducing fading of radio signals which includes separately receiving said signals, producing and maintaining a degree phase displacement in the signals received, combining the signals displaced 90 degrees, detecting the combined signals and-translating the detected signals.

5. The method of reducing fading of radio signals which comprises separately receiving signal energies, producing a 90 degree phase shift in the separately received signal energies, maintaining the 90 degree phase relationship despite relative variations in phase of the received signal energies, combining the energies displaced in phase by 90 degrees, and detecting and translating the combined energies.

6. The method of receiving radio signals which comprises separately receiving signals, combining said received signals, detecting said combined signals, and utilizing the voltage variations of said combined detected signals to maintain a substantially constant phase difference between the received signals before combination.

7. The method of receiving radio signals which comprises separately receiving said signals, producing a 90 degree phase displacement between said received signals, combining the phase displaced signals, detecting the combined signals and utilizing the voltage variations of said detected combined signals tomaintain the 90 degree phase displacement of the combined signals.

8. The method of reducing fading which includes making a plurality of signal energy collections, heterodyning the collected energies to a common different frequency, producing and maintaining a predetermined phase shift in the different frequency energies, combining the phase shifted energies, detecting the combined energies and translating the detected energies.

9. The method of reducing fading of received radio waves which includes heterodyning the received waves to a different frequency, producing a 90 degree phase displacement between the different frequency energies, combining the energies displaced 90 degrees, utilizing the combined energies to maintain the 90 degree phase displacement of the different frequency energies, and translating the combined phase displaced energies.

10. Apparatus for reducing the fading of received radio waves comprising a pair of antennae for collecting transmitted waves, a differential detector, means for feeding energies collected upon one antenna cophasally to the differential detector, means for feeding energies collected upon the other antenna, antiphasally to said differential detector, means for maintaining a predetermined phase displacement between the energies respectively fed to said differential detector, the last said means being responsive to an unbalancing of the output from said detector, and means for translating and utilizing the output of said differential detector.

11. Apparatus for receiving radio waves comprising a pair of antennae, a differential detector, means for feeding energy collected upon one antenna cophasally to said differential detector, means for feeding energy collected upon the other antenna antiphasally to said differential detector, means for maintaining a predetermined phase displacement between the energies fed to said difierential detector, and means for translating the output of said differential detector.

12. A radio receiving system comprising a pair of antennae, means for heterodyning the energies collected upon the antennae to an intermediate frequency, a differential detector, means for feed ing the intermediate frequency energy from one antenna antiphasally to said differential detector, means for producing a phase shift of substantially 90 degrees in the intermediate frequency energy from the other antenna, means for applying the phase shifted energy cophasally to said differential detector, and means responsive to the output of said difierential detector for maintaining the phase quadrature relationship between the intermediate frequency energies.

13. A receiving system comprising a pair of antennae, means for beating energies collected upon one antenna down to an intermediate frequency, a local oscillator associated with the other antenna for beating the waves collected thereon down to the same intermediate frequency, means for combining the intermediate frequency energies, and means responsive to the combined energies for so varying the frequency of said oscillator as to maintain a predetermined phase displacement between the intermediate frequency energies.

14. A receiving system comprising a pair of antennae, a pair of oscillators for beating the energies collected upon said antennae down to a common intermediate frequency, and means for so varying the relative frequencies of said local oscillators as to maintain a predetermined phase displacement of the intermediate frequency energies despite variations in phase of the energies collected upon said antennae,

15. A receiving system comprising a pair of antennae, a pair of oscillators for beating the energies collected upon said antennae down to a common intermediate frequency, means for combining the intermediate frequency energies, and means responsive to the combined energies for varying the relative frequencies of operation of said oscillators for substantially maintaining phase quadrature between the intermediate frequency energies.

16. In combination, a pair of antennae, a differential detector, a pair of oscillators, means for beating energies collected upon the antennae and energies from the oscillators so as to produce intermediate frequency energies, means for feeding intermediate frequency energy from energy collected upon one of the antennae antiphasally to said differential detector, means for feeding in termediate' frequency energy derived from energy collected upon the other antenna cophasally to said differential detector, and means responsive to the output of said differential detector to so vary the frequency of oscillation of one of said oscillators as to substantially maintain phase quadrature between the intermediate frequency energies fed to said differential detector.

1'7. In combination, a plurality of radiant energy collecting antennae, a receiving network for each antenna, means including a differential detector for combining the energies from said networks, a balanced two-way utilization circuit connected to said differential detector, and means including a phase correcting device operative in accordance with transient departures from a balanced condition in said utilization circuit for maintaining substantially constant the phase relationship between the energies respectively impressed upon said differential detector by each of said receiving networks.

MURRAY G. CROSBY.

US727931A 1934-05-28 1934-05-28 Receiving system Expired - Lifetime US2042831A (en)

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US2608683A (en) * 1943-10-28 1952-08-26 Gen Electric Phase comparison object locating system
US2678385A (en) * 1951-04-16 1954-05-11 Rca Corp Diversity receiver
US2786133A (en) * 1953-03-05 1957-03-19 Motorola Inc Diversity receiving system
US2844716A (en) * 1953-04-22 1958-07-22 Int Standard Electric Corp Radio diversity receiving system
US2955199A (en) * 1958-08-05 1960-10-04 Itt Radio diversity receiving system
US2966584A (en) * 1957-05-13 1960-12-27 Martin Co Receiving systems
US2975275A (en) * 1958-05-22 1961-03-14 Itt Combining system for diversity communication systems
US3036210A (en) * 1959-11-02 1962-05-22 Space General Corp Electronically scanning antenna empolying plural phase-locked loops to produce optimum directivity
US3040222A (en) * 1955-10-28 1962-06-19 North American Aviation Inc Servosystem adapted for angular measurement
US3195049A (en) * 1960-05-04 1965-07-13 Itt Radio diversity receiving system with automatic phase control
US3357018A (en) * 1964-11-06 1967-12-05 Itek Corp Mode-averaging diversity combining reception system for high-frequency radio waves
US3394374A (en) * 1961-08-11 1968-07-23 Packard Bell Electronics Corp Retrodirective antenna array
US3681695A (en) * 1969-09-02 1972-08-01 Raytheon Co Multipath compensation system

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US3471788A (en) * 1966-07-01 1969-10-07 Raytheon Co Predetection signal processing system
GB2227908B (en) * 1988-11-23 1993-12-08 Gen Electric Co Plc Radio receiver antenna systems

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2608683A (en) * 1943-10-28 1952-08-26 Gen Electric Phase comparison object locating system
US2505266A (en) * 1944-05-12 1950-04-25 Radio Electr Soc Fr Radioelectric communication device
US2577668A (en) * 1944-05-15 1951-12-04 Padevco Inc Circuit stabilizer
US2678385A (en) * 1951-04-16 1954-05-11 Rca Corp Diversity receiver
US2786133A (en) * 1953-03-05 1957-03-19 Motorola Inc Diversity receiving system
US2844716A (en) * 1953-04-22 1958-07-22 Int Standard Electric Corp Radio diversity receiving system
US3040222A (en) * 1955-10-28 1962-06-19 North American Aviation Inc Servosystem adapted for angular measurement
US2966584A (en) * 1957-05-13 1960-12-27 Martin Co Receiving systems
US2975275A (en) * 1958-05-22 1961-03-14 Itt Combining system for diversity communication systems
US2955199A (en) * 1958-08-05 1960-10-04 Itt Radio diversity receiving system
US3036210A (en) * 1959-11-02 1962-05-22 Space General Corp Electronically scanning antenna empolying plural phase-locked loops to produce optimum directivity
US3195049A (en) * 1960-05-04 1965-07-13 Itt Radio diversity receiving system with automatic phase control
US3394374A (en) * 1961-08-11 1968-07-23 Packard Bell Electronics Corp Retrodirective antenna array
US3357018A (en) * 1964-11-06 1967-12-05 Itek Corp Mode-averaging diversity combining reception system for high-frequency radio waves
US3681695A (en) * 1969-09-02 1972-08-01 Raytheon Co Multipath compensation system

Also Published As

Publication number Publication date
GB448147A (en) 1936-06-03
DE651549C (en) 1937-10-15

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