US1902234A - Receiver for continuous waves - Google Patents

Description

March 21, 1933. R. M. HEINTZ RECEIVER FOR CONTINUOUS WAVES Filed March 12, 1930 INVENTOR. RALPH N Him/T2 ATTORNEY Patented Mar. 21, 1933 UNITED sTArEs Parana oFFi-cs RAL'PH M. HEINTZ, OF PALO ALTO, CALIFORNIA, ASSIGNOR T0 HEINTZ & KAUFMAN, LTD., OF SAN FRANCISCO, CALIFORNIA, A- CORPORATION NEVADA RECEIVER iron conrrnnous wAvEs Application filed March 12, 1930. Serial No. 435,100.

My invention relates to receivers for radio waves, and particularly to receivers forcontinuous waves of high frequency and short wave lengths.

Among the objects of my invention are:

First, to provide a receiver which will translate the received wave into electrical oscillation of a definite predetermined frequency; second, to provide a receiver for continuous waves which does not produce interfering oscillations or waves of the same order of frequency as the received signal; third, to provide a receiver capable of practically unlimited amplification; and fourth, to provide a kreceiver' which is simply and easily adjustale. j

My. invention possesses numerous other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of my invention. It is to be understood that I do not limit myself to this disclosure of species of my invention, as I may adopt variant embodiments thereof within the scope of the claims. fRadio telegraph signals are transmitted with maximum efficiency and minimum of interference by the continuous wave or CW system. This system may be described from one point of view as the transmission of trains of waves corresponding to the telegraphic dots and dashes, the trains being of constant amplitude, i. e., the trains are not themselves modulated. The customary translating device for making the signals intelligible is a telephone receiver, but. since the waves are high above audible frequency some method must be used for first converting the high frequency oscillations into oscillations of low frequency, at the same time preserving the group frequency or dot and dash formation. Moreover, in shortwave or high frequency telegraph transmission the vacuum tube amplifiers used are very inefficient at the frequency ofv transmission,

and hence, even though-it may be desirable to 7 use graphic or other methods of recording rather than the customary phones, itis desirable to translate the incoming wave trains into lower frequencies before ampl fication. Broadly considered, only lnvention comprises a generator capable of producing oscillations of the required low frequency. Means are providedfor normally blocking the operation of this generator, and the re ceived oscillations or waves are applied to releasethis blocking means. Preferably the blocking means comprise a trigger tube which forms a grid leak for the oscillator, and thereceived waves are applied to the grid of this tube to :permit the grid current required for the oscillator operation to flow. The drawing isa circuit diagram showing one form of the receiver of my invention.

The form of my invention here shown comprises an oscillator using a'pair of vacuum tubes 3 and 4, having the custom'ary anode, control electrode, and cathode of filament, the latter being energized by the battery 6 through a filament circuit 7. Connected to I the tubes is an oscillating circuit comprising a condenser 8 and two inductance coils 9 and 11 which are arranged to have zero mutual coupling. The plate of the tube 3 isconnected to the inductance coil 9, and the plate 7 of the tube 4 is connected tothe coil 11. Di-.

rect current for the tube is supplied from a suitable source 12 through a choke coil 13 connected to the junction point of the two inductances. v o

The control electrode'of the tube 3 is connected through a blocking condenser 14110 the plate of the tube 4; the control electrode of the tube connects through a similar blocking condenser 16 to the plate of the tube 3. The .two control electrodes are connected together through the choke coils 17 and 18.

A coil 19, coupled to thecoil 11, draws [energy from the oscillating'circuit and. de-

livers it to the translating device-whichv is exemplified by the head phones 21.

In order that such an oscillator may operate it must be provided with a grid leak, as otherwise the controlelectrode will promptly become so negative as to permit no current to flow. Such a leak is provided by the tube 22 which'has a filament circuit 28 connected through a high frequency choke 24 to the junction of the choke coils 17 and 18.

The plate of this tube is connectedthrough a second choke 26 with. the oscillator filament circuit 7 The negative charge accumulated. by the control electrodes of the oscillator tube provides the plate potential for the tube 22.

A parallel oscillating circuit comprising an inductor .27 and variable condenser 28 is connected between the plate and control electrode of the tube 22 through a blockingcondenser 29. A grid leak 31 connects with the filament circuit 23in such manner that the voltage drop through a rheostat 32 provides a negative bias which blocks current 'fiow through the tube. The receiving circuit is coupled in the usual manner through a coil 36 to a circuit comprising the antenna 37 and ground 38 or other suitable absorbing circuit.

It will be noted that'the receiving circuit 27 -28 is of the regenerative type, since plate and control electrode are connected to points of opposite potential. It is to be understood that this circuit is preferably not permitted to oscillate, and that if desired a nonregenerative circuit'm'ay beuse-d, the incoming sig-.

nals being impressed between filament and ,grid of the tube 22in the usual way.

The tube 22 may be referred-to as a trigger tube. Its'connection is such that it'norrnally .permits no current to ifiow,'and the oscillator is therefore normally'blocked. When a received signal is impressed upon the grid of the trigger tube itslpos'itiv'e swings permit a flow of current between the oscillator control electrode and the filament circuit 7 releasing the oscillator and permitting it 'to operate. When the signal cases the oscillator immediately blocks again.

The circuit-may be considered either as a I self-blocking oscillator with releasing means ;;provided,' or as anormal oscillator to'vvhich Ierateat audio frequency. Instead of its outputbein'g applied directly to the'phones or othertrans'lating device,-this output may be {amplified at an intermediate frequency and V the amplified signal applied to the'gridofa secondtrigger tube controlling an audio frequency oscillator. The reduction of frequency' by multiple stages is sometimes advis- -able-,but does not difi'er infprinciplefrom the single 'stagereduction here shown.

It is to be 'notedthat the frequency of the oscillator isfiXed, and does not depend in wayupon'the frequency of the incoming signal as is the case with the heterodyne method of reception. For this reason only .the'receiving circuit and not the. oscillating circuit need'be provided with variabletuning devices, and maximum amplificationlmay "-be obtainediby' making the translating Idevi'ce sharplyfres'ponsive to the amplifier .fre- I quen'cy. Moreover, the frequency of the oselectrode may be isolated or controlled through a trigger tube may be used, and any form of regeneratlve or nonregenerative receiving circuit may be connected to the *trigger tube.

2. A receiver for continuous waves comprising a self-blocking oscillator-having "a cathode and a control electrode, a trigger detector tube having'aplate circuit connected between the cathode and control electrode of said oscillator, said trigger detector tube also having a control electrode, and a'reg'enera'tive circuit including a blocking condenser associated with the-control electrode of said trigger tube and arranged 'normallyto block current flowin the plate circuit of saidztube and-to release saidfiow when a receivedwave is impressed thereon.

-3. Areceiver for. continuous waves com- ,prising'a vacuum'tube oscillator for'generat- "ing a frequency lower than-thatof the waves to bereceived, a trigger detectorltube forming a grid "leak for said oscillator and 'having a control electrodefand a regenerative circuit including. a 1 blocking condenser connected'to said control electrode and arranged [normally to block current flow through said trigger tube and to releasesaid flow when a received 'wave' isflnipressed'thereon.

4. Areceiver'for continuous waves -comp'rls'lng a vacuum tubeosclllatorfor generating afrequencylower 'than'that of the waves to be received, a trigger vdetector tube forming afgridleak for said oscillator andhaving a control electrode, and -a-re'generative circuit including a blocking condenser connected'to sai'dgco'ntrol electrode and including means 'for impressing a potential on said control jelectrodersu'lficient normally to block current 'flowthr'ough said trigger-tube." I 5. A receiver fOfCOIltlIlllOllS waves comprising an oscillator having acathodeand' a control electrode, a trigger detector tubehaving a cathode, an anodeand a controlelectrode, the cathode of said triggertubdbeing connected to the oscillator control electrode and the anode of said trigger tube being connected to the oscillator cathode, a regenerav tive receiving circuit connected to the trigger control electrode, and means for impressing a mean potential on said trigger control electrode suflicient substantially to block current flow through said trigger tube.

6. A receiver for continuous waves comprising an oscillator, a trigger tube forming a grid leak for said oscillator, and a receiving circuit regeneratively connected with said trigger tube.

In testimony whereof, I have hereunto set 1 my hand.

RALPH M. HEINTZ.

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