Патент USA US2134590код для вставки
@et 25, 1938A 2,134,35590l B. TREvoR 'ET AL lSHORT WAVE‘REGEPTION Original Filed Dec. 6, 1935 ‘ululull Illll’ < >. > Il" 'u 0^ Q9 o uw, x _sin FM2„Em.EAlNI unév. INVENTORS BERTRAM TREVOR AND ~ î e" ` ;’_ ALP ‘W. GEORGE @H7/1% ATTORNEY. 2,134,590 Patented Oct. 25, 1938 PATENT OFFICE ' .2,134,590 Y . sHoR'rjWAvE RECEPTION" VBertram Trevor and Ralph Waldo George, River head, N. Y.,.a`ssignors to Radio Corporation of America, acorporation of Delaware’ Original application December 6, 1935, vSerial No. 53,136. Divided andthis application Septem ber 16, 1936, Serial' No. 100,974 . L:Í claims. (ci. 25o-_20) This application is a division of our copend ing application Serial No. 53,136, ñledDecember c, 1935. ` , f ~ » Y Ultra short wave lengthV receivers, such as de scribed in our parent application," employ suc cessive stages of heterodyning» >Asthe local os cillators vary in frequency with changes in tem Which‘is grounded as shown.‘ The far end of the second rod 24 is tuned by means of the vari able tuning condenserv 28V. The rod. 2i and con denser 28 form a second non-radiating highly V selective circuit and adjusted to have a resonant curvevvvhich overlaps the resonant curve of Vthe rod lli-condenser 2l! combination. In this Way, perature, the differencev or slum* frequency cur the-frequency'pass band-width of the two pre rents change in frequency,` normally requiring i selector circuits i4, 2li, I2 and 24, 26, 28 is fur retuning or the use of beat frequency amplifiers ther widened. having wide pass bands. . Returning, obviously, r The received filtered energy is then fed to the is objectionable fromthe operating pointof `ViewV grid of -a` first detector tube 34. This first detec and use of wide pass band amplifiers' is undesira tor is also vsupplied with heterodyning energy ble since they increase the overall noise level- or from a ñrst local oscillator comprising a discharge ` backgroundl in theffinal receiver output. t ' To overcome these disadvantages is theïmain object of our invention.A This object is effected by,V utilizing the follow ing relations of frequency-"of operation and tem 20 perature coeñicient of frequency: 1. , When the ñrst beating oscillator is operated on the high frequency side of the signal, both the ñrst and second beating oscillators are made to have the same sign of temperature coefficient, re 25 gardless of Which side of the first intermediate i frequency the second beating oscillator is on. 2. When the first beating oscillator is onV the low frequency side of the signal, the temperature coefficient of the first and second beating oscil lators are made opposite in sign in order to have frequency compensation which will take place regardless of Which side of the first intermediate frequency the second beating oscillator is on. Our present invention is more fully described in connection with the accompanying drawing which is a Wiring diagram of the first and sec ond heterodyníng stages of our ccpending appli cation hereinabove referred to. Turning to thedrawing, energy collected upon 40 the receiving antenna 2 is fed through a cou pling transformer having a primary Il and a sec tubeî?lß. , 5 ‘ _ „ ’ 4--As described in more detail in our copending parent-application Ser; No. 53,136, the oscillatory - energy is injected into a thermo-responsive fre quency > compensating Vvmeans 90 and thence through the cathode leads of the detector tube 34 for producing therein a beating of the oscillator frequency with the incoming frequency collected by the antenna 2. The oscillator, itself, is tuned by means of a coil 58 and tuning condenser 60 in the plate circuit. A by-pass condenser B2 sepa rates the plate potential lead @It from the ground ed device âû. The beat frequency energy is resonated in the plate circuit of the first detector 3a by means of a tuning coil 42 and tuning con denser 44, both of which are adjusted to the beat 30 frequency. The beat frequency energy is fed through a by-passing condenser ¿56 to a first beat frequency amplifier and then fed to a second detector |34. The latter is supplied with oscil lations from a second local oscillation generatorV 35 having a discharge tube Mil and the beat fre quency output from the second detector is fed into a second intermediate frequency amplifier Whose output is utilized as desired. The‘first local oscillator and the second local oscillator are made to -have temperature coefficients of Concentrically mounted rWithin the _ frequency such that despite variations in am cylinder i2 there is a rod or metal pipe i4 bient temperature, the final beat frequency ener grounded at its left-hand end I6 -and connected gy fed to the third detector and second inter 45 to ground at its right-hand end through a damp mediate frequency amplifier remains substantial 45 ing resistor I8 and variable tuning condenser 20. ly constant. , The metal rod I4 within the metal cylinder I2 The structural details of the thermo-respon forms a sharply selective input circuit, standing sive frequency compensating means 90 may be t `_ondary 6. current waves being set up thereon by virtue of 50 the input from the secondary 6 and by virtue of the tuning of condenser 20. The received energy resonated in the rod M and condenser 20 is fed through a 10W impedance connection 22 to a second rod, tube or metallic 55 pipe 24 mounted Within a second cylinder 26 in accordance with the disclosure of our afore said parent application, or they may be in ac 50 cordance with other devices Well known in the art having as their function to stabilize the fre quency of an oscillatory circuit and to render said frequency relatively independent of temper ature changes. 55 2 ' ` ' 2,134,590 Preferably, the second local oscillator |40 is tuned below the frequency of the intermediate frequency oscillations produced by the first de tector 34, and the first local oscillator 48 is ad justed to produce oscillations at a frequency above the incoming wave frequency. Then, if the two local oscillators have the same or ap proximately the same, frequency variation with ambient temperature changes, the resultant 10 beat-frequency in the circuit |44 will remain ef fectively constant despite changes in the sur rounding temperature. The same result may be obtained by having the desired changes in frequency with tempera ture are produced. Having thus described our invention, what we claim is: l. In a heterodyne receiver of high frequency waves a ñrst local oscillator, means for hetero quency, a second local oscillator, means for oscillator 48 adjusted to produce oscillations of a frequency lower than the incoming wave and thermo-responsive means for so controlling frequency while at the same time producing the desired beat frequencies. To summarize, if the first beating or local oscil lator is operated on the high frequency side of the signal, both beating oscillators for frequency compensation should be made to have the same sign of temperature coefficient regardless of which 25 side of the first intermediate frequency the sec ond beating local or heterodyning oscillator is on. On the other hand, if the first beating oscillator is on the low frequency side of the signal, fre quency compensation will occur provided the tern 30 perature coefficient of the second beating oscil lator is made opposite in sign to that of the first. This latter effect will take place regardless of which side of the first intermediate frequency the second beating oscillator is on. The desired frequency temperature coeflicient for the ñrst and second local oscillators may be obtained by proper choice of the materials used in their construction, particularly the materials used in the frequency controlling circuits. If 10 dyning said waves with output energy from said oscillator thereby to produce a first beat fre heterodyning Waves of said first beat frequency with» output energy from said second local oscil lator, thereby to produce a second beat frequency, the second local oscillator` |40 tuned above the first intermediate-frequency and the first local 35 desired, the frequency controlling circuits of each oscillator may be provided with a movable tuning condenser plate which is moved in such a way by a temperature responsive bi-metallic strip that the» frequency relationship between the two os cillators that said second beat frequency remains substantially constant, despite variations in the 20 ambient temperature. 2. Apparatus in. accordance with claim 1 and having the first local oscillator adjusted to a higher frequency than that of the waves with which its output energy is heterodyned, said thermo-responsive means being operable to Vary the frequency adjustments of the two said oscil ' lators in the same direction upon the occurrence of a given change in the ambient temperature. 3. Apparatus in accordance with claim 1 and having the first local oscillator adjusted to a lower frequency than that of the waves with which its output energy is heterodyned, said thermo-responsive means being operable to si multaneously vary the frequency adjustments of 35 _the two said oscillators opposingly. BERTRAM TREVOR. RALPH WALDO GEORGE.