US1917395A

US1917395A - Frequency determining means

Info

Publication number: US1917395A
Application number: US396895A
Authority: US
Inventors: Runge Wilhelm
Original assignee: Telefunken AG
Current assignee: Telefunken AG
Priority date: 1928-10-16
Filing date: 1929-10-02
Publication date: 1933-07-11
Anticipated expiration: 1950-07-11
Also published as: FR37916E; GB332834A; DE509946C; FR683292A; GB341766A

Description

July 11, 1933. RUNGE 1,917,395

FREQUENCY DETERMINING MEANS Filed Oct. 2, 1929 INVENTOR WILHELM RUNGE ATTORN EY Patented July 11, 1933 UNITED STATES PATENT OFFICE FUR DBAH'IIDBE TELEGRAPHIE M. B. BL,

01? GERMANY OF BERLIN, GERMANY, A CORPORATION FREQUENCY DETERMINING HEARS Application flied Octglger 1929, Serial No.

When a suppressed carrier is boost'ed (restored) in the receiver the frequency of the booster has to synchronize with that of the suppressed carrier with the exception of a few cycles. The problem thus results n and amounts to the extensive synchronization of two transmitters. The most perfect means is the independent synchronism of both transmitters. This method is simpl applicable to telephony on long waves. or waves of about 15 meters as they are used today in transoceanic telephony a precision of about 10' would be required which is not obtam able by the methods hitherto known for producing adjustable constant senders.

Of all the processes wherein a synchronizing frequency emitted by the transmitter serves to hold the boosted carrier on the correct frequency the best known comprises the method of emitting jointly the remainder of a carrier, of workin it through the receiver individually and o settin it therein for heat reception with the booste carrier. The frequency of the carrier booster is then to be set by hand or automatically in such a way that the beat note will have a itch as low as possible or that it will drop down to zero.

In transoceanic telephony where the intensity of sound is known to be subject to considerable variations due to the time of the day, an auxiliary tone is emitted besides the voice which tone, being of a higher pitch than the highest voice frequencies emitted, is kept within the limits of constant intensity of sound by a process of automatically controlling the amplification to the effect that the slow hourly variations in the intensity of transmission are compensated. In cases where only one side band is used for reception with the result that the carrier and the other side band is being suppressed, whereas the carrier is boosted at the receiving end, this auxiliary tone is transmitted as the only frequency lying at the distance of its pitch at the side of the carrier suppressed.

After boosting with an artificial carrier and after demodulation the auxiliary tone will then reappear asan independent frequency. If, however, the boosted carrier varice from the suppressed carrier by n-cycles,

396,895, and in Germany October 15, 1928.

in that case the auxiliary tone, too, after the modulation will vary by n-cycles from the auxiliary tone originally used for modu lation. Accordin to the invention, this auxiliary tone is use to synchronize the carrier booster. The auxiliary tone, for this purpose, is sent into a device which, for exam le, actuates a relay in such a way that the re ay is thrown to one side, in case the auxiliary tone has a lower pitch than its nominal frequency, whereas it is thrown to the opposite side, in case the auxiliary tone has a higher pitch than the nominal frequency. The circuits closed by the relay contacts cause a detuning of the boosted carrier in such a way that the auxiliary tone is tuned up (adjusted) to its nominal frequency. Thereby, however, the auxiliary tone, too, is made to synchronize with the suppressed carrier. The regulation of the frequency of the auxiliar tone has to be so exact that the variations sti 1 existing between the boosted carrier and the suppressed one may not exceed the allowable limits.

The figure shows a diagrammatic sketch illustrating one embodiment of the invention.

The reception coming from the antennae 1 is amplified in the receiver 2, a side band and the carrier are eliminated in case those were emitted along. By means of the highfrequency generator 3 a carrier corresponding to the suppressed carrier is boosted or restored again to the receiver 2 ahead of the rectifier or demodulator in the receiver. The signals thus rectified are sent into two filter chains of which the filter chain 4 permits the voice frequencies to ass and conducts them further to the lines E while being impermeable to the frequencies of the auxiliary tone. The filter chain 5 is only permeable to the auxiliary note but not to those of the voice, and furnishes, by way of transformers 6 and 7 auxiliary tone potential to the grids of two rectifiers 8 and 9 connected in counter-phase. The secondary winding of transformer 6 is tuned to the normal frequency of the secondary tone by means of the condenser 10 and potential oscillations therein act in phase opposition upon the grids of the tubes 8 and 9. The transformer 7 is not tuned and the potential oscillations in the secondary winding thereof energizes both grids in equal phase, since this winding is connected at one end to the filaments of 8 and 9 and at the other end to the midpoint of the secondar winding of transformer 6. The potentia s impressed upon the grids by the transformers 6 and 7 are in phase quadrature to each other when the auxiliary tone is in synchronism with the frequency to which the secondary side of the transformer 6 is tuned by the condenser 10. Therefore, the anode currents of both tubes 8 and 9 are equal to each other, the relay 11 is not energized. If, however, the auxiliary tone frequency 6 varies from the resonance frequency to which the secondary side of the transformer 6 is tuned in that case the potentials, at the terminals of the transformer 6 are not out of phase by ninety degrees to those at the transformer 7. In consequence thereof the one id will receive a higher alternating potential than the other grid. The rectified currents of the tubes 8 and 9 are therefore of different magnitude and the rela 11 will be thrown to the one side or the other according to the direction in which the frequency of the auxiliar tone has shifted.

When, according to t e connection illustrated, the relay is thrown in one direction the grid of the tube 12 is charged positive by an auxiliary battery 13, whereas the latter is charged negative when the relay is thrown in the opposite direction. The resistance 14 and the condenser 15 introduce a time lag in the potentials applied to the grid of 12 and varies slowl the potential of the grid of 12 after the grid relay has been actuated. The anode direct current of the tube 12, thus varied, is fed a ain to the carrier boosting device and by shifting of the carrier boosting frequency to this extent causes correction of CERTIFICATE OF Patent No. 1, 917,395.

the variation of the auxiliary tone from the nominal frequency.

What I claim is:

1. In apparatus to receive high frequency oscillations which are signal modulated and also modulated by a super-audible frequency, a receiver including a detector, a filter to the super-audible frequency connected to said detector, thermionic means for producing potential variations representative of variations in the frequency of the super-audible frequency, a high frequency generator connected with said receiver, and means for utilizing the potential variations representative of changes in the super-aud1ble frequency for controlling said high frequency generator.

2. In radio apparatus to receive high frequency oscillations modulated by signal frequency and by a control frequency, a radio receiver including, a rectifier, means for filtering out the signal fr uency connected with said rectifier, an oscillation generator connected with said receiver, means for filtering out the control frequency, a pair of thermionic tubes having input and output electrodes connected in opposition, means for difl'erentially coupling the input circuit of said thermionic tubes to the output circuit of said control frequency filter, means for cumulatively connecting the input circuit of said thermionic tubes to the output circuit of said control frequency, a thermionic amplifier having its input circuits adapted to be connected alternately to the terminals of a biasing source by means of a rela connected with the output circuit of said fi rst named thermionic tubes and a connection between the output electrodes of said thermionic amplifier and said high frequency generator.

"HELM RUNGE.

CORRECTION.

July 11, 1933.

WILHELM RUNGE.

It is hereby certified that error I, after "filler" to read with this correction therein the case In the Patent Office.

appears in the printed specification of the above numbered patent requiring correction as followp: Page 2, line 72, claim insert the word tuned; and that the said Letters Patent should that the same may confom to the record of Signed and scaled thia 5th day of December, A. D. I933.

(Seal) F. M. Hopkins Acting Comiaaioner of Patcntl.

5 to the midpoint of the secondar tential oscillations in the secondary winding thereof energizes both grids in equal phase, since this winding is connected at one end to the filaments of 8 and 9 and at the other end winding of transformer 6. The potentia s impressed upon the grids by the transformers 6 and 7 are in phase quadrature to each other when the auxiliary tone is in synchronism with the frequency to which the secondary side of the transformer 6 is tuned by the condenser 10. Therefore, the anode currents of both tubes 8 and 9 are equal to each other, the relay 11 is not energized. If, however, the auxiliary tone frequency 6 varies from the resonance frequency to which the secondary side of the transformer 6 is tuned in that case the potentials, at the terminals of the transformer 6 are not out of phase by ninety degrees to those at the transformer 7. In consequence thereof the one id will receive a higher alternating potential than the other grid. The rectified currents of the tubes 8 and 9 are therefore of different magnitude and the rela 11 will be thrown to the one side or the other according to the direction in which the frequency of the auxiliar tone has shifted.

When, according to t e connection illustrated, the relay is thrown in one direction the grid of the tube 12 is charged positive by an auxiliary battery 13, whereas the latter is charged negative when the relay is thrown in the opposite direction. The resistance 14 and the condenser 15 introduce a time lag in the potentials applied to the grid of 12 and varies slowl the potential of the grid of 12 after the grid relay has been actuated. The anode direct current of the tube 12, thus varied, is fed a ain to the carrier boosting device and by shifting of the carrier boosting frequency to this extent causes correction of the variation of the auxiliary tone from the nominal frequency.

What I claim is:

"HELM RUNGE.

CERTIFICATE OF CORRECTION.

Patent No. 1, 917,395.

July 11, 1933.

WILHELM RUNGE.

It is hereby certified that error i, after "filler" he read with this correction therein the case In the Patent Office.

appears in the printed specification of the above numbered patent requiring correction as followp: Page 2, line 72, claim insert the word tuned; and that the said Letters Patent should that the same may confom to the record of Signed and sealed thia 5th day of December, A. D. 1933.

(Seal) F. M. Hopkins Acting Comieeioner of Falcon.