US1789303A - Electrical signaling - Google Patents

Description

Jan. 20, 1931. a H. CHIREIX. 1,789,303

ELECTRICAL. S IGNALING Filed March s, 1 92s .2 Sheets- Sheet 1 A I 1 I I I i i l i I i l i I i 61 l I 1 I 1 *e n I i l g I a -r\ I gl- I Qlk I llNVENTOR mm CHIREIX Jan. 20, 1931. QHIREIX 1,739,303

ELECTRICAD SIGNALING Filed March 23, 925 2 Sheets-Sheet 2 4 LOCAL 65mm 70A INVENTOR HENRI CHIREIX.

ORNEY Patented Jan. 20,1931.

LIN-Iran STATES PATENT OFFICE HENRI GHIREIX, or rams, FRANCE jEIiECTRIGAL SIGNALING Application filed March 23, 1925, Seria1 No. 17,624, and in France June 17, 19:24. I

My invention relates toelectrical signal: ing and. more particularly to receiving systems for the reception of signal waves. 1

An object of my invention is the provision of simplified apparatus having-thefollowing advantages when employed with receiving systems designed-for the reception of comparatively high. frequency waves:

1. Effecting the reception of comparatively' low frequency waves as well as high frequency waves by said high frequency receiving system.

2..Efiecting reception over a verygreat range of signal. frequenciesradio telephony waves without distortion even when the frequency is low.

4. Minimizing the efiectsof'dis'turbingoscillations by the use of an aperiodic antenna or a; Beverage antenna.

Other objects and advantages of my invention will be apparent from the'following description taken inconnection with the accompanying drawings in which Fig. 1 is a schematic diagram of'a modification of my invention.

Fig. 2' is a schematic diagramof another modification disclosing alternative features.

Referring to Fig. 1-, the receiving system I comprises two parts, A and B, the part A containing'the necessary apparatus designed for the normal reception, detection and amplification of comparatively high frequency waves; while the part B comprises theneces= sary' apparatus for use together with the receiver A for readily effecting the reception, amplification and detection of comparatively low frequency waves. 1

The receiver A comprises a locally tuned circuit 1 which ordinarily is the antenna cir cuit, a radio frequency triode amplifier 2', a triode detector 3, two audio frequency-triode amplifiers 4' and 5 and a signal responsive device 6.

The local circuit 1 comprises an inductance coil 7 shunted by variable condenser "8 for tuning the said local circuit to the incoming high frequency signal waves. The grid and filament of amplifying triode 2 are connected across the local circuit, while theplate fila- 3'. Effecting regenerative amplification of merit circuit is coupled to the grid filament circu'itof: detecting triode 3; by means of transformer 9. The plate filament circuit of detecting triode- 3 is inductivelycoupled to the grid filament circuitof amplifying triode 2 by'means of the coils 7 and 105 7 It is'to be noted that this feed-backoccurs atghigh radio frequency;

The plate filament" circuit of detecting-triode 3 is inductively coupled to the input ofthe audio frequency amplifier t'r'iode' by means of transformer 11. The output circuit of trio'de 41s in turn inductively coupled to the input circuitof audio frequency amplifier triode, 5 by means of transformer 12.

the output circuit of amplifying triode 5. The usual commonfilainent battery and plate battery for supplyingthe various filaments i and plate circuits are provided as shown".

The part B comprises alocal circuit 13, a radio. frequency amplifyingtriode 14 and a local generator of auxiliary waves 15. The local'circuit 13- comprises an inductance coil 16' and a variable condenser 1:7"connectedi'n shunt therewith for tuning the local circuit to the: comparatively low fr uencywaves;

' The input of amplifying triode 14f is connected across the local circuit 1-3 while the output is connected across the local circuit 1. The output circuit of amplifying triode 11 is also inductively'coupled to a local generator of auxiliary waves 15 by ineans' of the transformer18; As the" local oscillator with its associated circuits is wellknown in the art, a detaileddescription thereof is unneces sary.

An antenna '18, preferably ofthe-aperiodic' or Beverage types, is connected to one-termizeal of the local circuit 13,- the'other terminal being connected to the ground. 7

It is customary to'call the combination of two adjacentradio frequencies which differ by an audio frequency, beating, and to call the combination 'of' aradio frequency" and an audio frequency, which differ by a radio frequency, modulation. My invention involves the combination of a radio frequency with another radio frequency, resulting in the production of still other radio frequencies. The

A signal responsive device 6 is connected. in

7 cycles.

magnitude of these frequencies are such that the two combined frequencies differ by a frequency which is nearer the larger than the smaller, so that the phenomenon, considered in terms of an audio frequency, is more like modulation than beating. I shall therefore thruout this specification use the term modulation ina broad sense, meaning the combination of frequencies s difierent that their difference is a frequency closerto the greater than to the smaller of the two origi'- nal frequencies. I shall explainmy invention by a specific example as follows.

Suppose that the. receiver A is arranged to respond to frequencies in the neighborhood of 500,000 cycles, while it is desiredto receive a comparatively low frequency, say 50,000 In this case the local circuit 13 is tuned to 50,000 cycles by means of the variable condenser 17 while the local oscillator is arranged to generate waves at a frequency of 450,000 cycles. These auxiliary waves are modulated by low radio frequency waves, and the resulting modulated wave will have components or side frequencies of 500,000 cycles and 400,000 cycles.

The local circuit 1 is tuned to one of the side frequencies, in this case the 500,000 cycle frequency, by means of the variable condenser 8. The side frequency component, which represents the effect of the low radio frequency, is also modulated in substantially the same manner as the transmitted signal wave. Hence, in telephone work, the side frequencies are really side bands. The modulated high frequency wave is fed to the receiver A where it is suitably detected andiamplified. By obtaining a proper frequency in the local oscillator, the receiver A may be efficiently applied to any frequency lower than its normal range; This arrangement permits the regenerative amplification without distortion because feed-back is not attempted at'the low radio frequency.

Another modification fitted for greater received radio frequency amplification is represented in Fig 2. Referring to that figure,

the receiving system comprises an antenna circuit having preferably an aperiodic antenna 20 and a tuning coil 21 both connected in series and grounded at G as shown. A resistance 22 is'connected across the tuning coil 21, as shown, and it helps insure aperiodicity. A

The input of amplifying triode 23 is connected across the resistance 22 while the output of amplifying triode 23 is connected to the input of amplifying triode 24 by means of a well known resistance coupling device comprising resistances 25 and 26 and condenser 27. A condenser 28 is connected across the resistance 25 to by-pass high frequency energy collected by the antenna, and so prevent the passage of undesirable high frequency waves through the amplifying vsistance 37 The output of amplifying triode 29 is con- A nected to theinput of amplifying triode by means of a well known resistance coupling device comprising resistances 36 and 37 and a condenser 38' connected as shown. A resonant shunt, comprising inductance coil 39 and condenser 40 connected in series therewith, is connected The output circuit of amplifying. triode 35 comprises a coil 41 and an inductance coil 42 connected in series as shown. A variable condenser 43 is connected across the terminals of inductance coil 42 while a local generator of auxiliary Waves is inductively coupled to the output circuit of amplifying triode 35 by means of the coils 41 and 44. A

coupling condenser 45 is provided for coupling the high resistance 46 to the above described system.

As a specific example of the operation of this system, assume that signal waves of'a frequency of 20,000 cycles are to be received, and that a frequency of 220,000 cycles is desired. The local generator is then adjusted to produce auxiliary waves at a frequency of say 200,000 cycles. These waves are modulated by the signal duced side bands with mean frequencies of 180,000 or 220,000 cycles. Theparallel resonant circuit 42, 43 is tuned to one of these frequencies,say 220,000, and is excited by that component. The output is taken from opposite terminals of the resistance 46, which is connected across the resonant circuit 42, 43 and its source of potential- The condenser 45 stops the steady component but passes the alternating component of the plate potential. I

The series resonant shunt, comprising inductance coil 33 and condenser 34, .is preferably tuned to 220,000 cycles; while the series resonant'shunt, comprising inductance coil 39 and condenser 40, is preferably tuned to 420,000 cycles. These resonant shunts will therefore prevent the production of the desired side frequency from certain interfering waves and will also attenuate the effects of waves having a frequency equal to the side frequency. Thus, if some near station transmits at a frequency of 220,000'cycles, its influence would seriously affect the parallel resonant circuit 42, 43, but'the series resonant circuit 33, 34 short circuits this energy before across the terminals of rewaves, and there are prolecting modulated it can reach the output circuit. A short wave transmitter tuned to a frequency of 420,000 is also found troublesome, probabl 1 because it coacts with the local oscillator to affect the circuit 42, 43 by the difference of their frequencies, and such 420,000 cycle energy short circuited by the series resonant circuit 39, 40. Furthermore, the spread of high frequency energy and its harmonics from the local oscillator thru the preceding amplifying tubes by means of the natural capacitive coupling within the tubes is effectively reduced by the resonant and capacitive shunts employed.

To state the frequency relations more generally, the resonant shunt comprising the inductance coil 33 and condenser 34 is tuned to a frequency equal to the mean signal frequency to be received plus or minus the fre-' quency of the auxiliary waves, that is, it is tuned to the same frequency as the receiver; While the resonant shunt comprising inductance coil 39 and condenser 40 is tuned to a frequency equal to the mean signal frequency to be received plus or minus twice the auxiliary frequency, in other words, to twice the frequency of the received energy. The local circuit comprising the inductance coil 42 and the variable condenser 43 is tuned to the desired side frequency. The capacity 28, and the series resonant circuits 33, 34 and 39, 40 constitute a filter which rids the tube 35 of a great many interfering and parasitic oscillations.

Disturbing influences due to static and interfering signal waves are very largely eliminated owing to the fact that none of the elements constituting this system are tuned to the signal frequency or even to a frequency in the neighborhood of signal frequencies. It is to be understood that any kind of re ceiving apparatus arranged for short wave be connected across the resistance 46, an example being the receiver A'in Fig. 1.

While I have shown and described various embodiments of my invention, I do not limit myself to the same but may employ such other modifications as come within the spirit and scope of my invention.

I claim:

1. The method of changing modulated low radio frequency energy to mondulated high radio frequency energy which consists in collow radio frequency energy, generating unmodulated high radio frequency energy, using the modulated low radio frequency energy to modulate said uninodulated high radio frequency energy and separating from the resulting energy an energy band the main frequency of which is a side frequency of said modulated high radio frequency energy. Y

2. The method of receiving energy of relatively low radio frequency with a receiver latedenergy. of'a relativelyhigh radio frequency;v modulating thelatter energy with he collectedenergy,and-utilizing for recep:

tion on'e of. the saidfrequency componentsof the locally modulated. high; radio frequency energygq 1 g 3.: Apparatus; for; the, reception of riel-a--- tively low radio frequency energy; comprising; an antenna, aregenera'tive receiver tuned to? a relatively high radio frequency, coupling means including an oscillator tuned to oscilr' late at-a frequencyi-v which. is the sum or dif-= ference ofthe low and high radio-frequencies. vmeans 1 to: prevent energy at relatively high frequency from passing frometheans tennathrough-thecoupling means;

4: Ap'par atus; for the recept' on of? energyat low radio frequency f comprising anv an ten-na, receiver tuned to. a high: radio frequency F, and coupling; means including. a. low radio frequency amplifier connectedtothe antenna and anoscilla'tor tuned to gen.- erate an u'nmodulatedwave of highradio fre.-; quency (F connected to the output. of; saidiztnaplifii; 1; l

5. In combination, an oscillator adapted to produce unmodulated energy, means for collecting signal energy, means coupling the collecting means to the oscillator, so that'the signal energy modulates the energy generated V quency energy, and detecting means coupled to the tuned circuit.

7 In combination, an aperiodic antenna, a resistance coupled radio frequency amplifier coupled to an oscillator the energy of which is modulated by the received amplified energy, a resonant circuit tuned to a side frequency of the modulated energy, detecting means coupled to the resonant circuit, and a filter system adjusted to prevent received energy having the frequency to which the resonant circuit is tuned from affecting said resonant circuit.

8. The method of reception which consists in collecting modulatedsignal energy at a low frequency, locally generating unmodulated energy at a relatively high'radio frequency, modulatingsaid latter energy with said modulated signal energy, and'utilizing one of the side frequency components of the modulated high radio frequency energy.

9. A method of receiving modulated low radio frequency energy with a high radio frequency receiver which consists in collecting said low radio frequency energy, locally generating unmodulated energy at a high radio frequency within the range of the said receiver, modulating said latter energy with said collectedenergy, and detecting the modu lated high radio frequency energy.

10; In a method, as defined in claim 9, the step of detecting only the upper side frequency of the modulated high radio frequency energy.

11. A method of reception which consists in collecting modulated signal energy at a low radio frequency, locally generating unmodulated energy at a higher radio frequency, modulating said higher radio frequency energy with said modulated signal energy, detecting the modulated higher radio frequency energy, and suppressing all collected energy which has a frequency equal to said modulated higher radio frequency energy.

HENRI CHIREIX.

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