US1985046A - Electrical wave production - Google Patents

Electrical wave production Download PDF

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Publication number
US1985046A
US1985046A US713764A US71376434A US1985046A US 1985046 A US1985046 A US 1985046A US 713764 A US713764 A US 713764A US 71376434 A US71376434 A US 71376434A US 1985046 A US1985046 A US 1985046A
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waves
frequency
kilocycles
series
kilocycle
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US713764A
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Warren A Marrison
Larned A Meacham
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AT&T Corp
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Bell Telephone Laboratories Inc
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Priority to FR786456D priority patent/FR786456A/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J1/00—Frequency-division multiplex systems
    • H04J1/02—Details
    • H04J1/06—Arrangements for supplying the carrier waves ; Arrangements for supplying synchronisation signals

Definitions

  • FILTE FILTER 2.10 Kc. 12 32,52, 72- 2 2 K C- WAMARR/SO/V 4 K.C. GENERATOR INVENTORS- UM Q ATTORN V I4 34 54,74-234 K.C.
  • Patented Dec. 18, 1934 UNITED STATES ELECTRICAL WAVE PaoDUc'rIoN i Warren A Marrison, Maplewood; and Larned A. Meacham Montclair, N. J., assignors to Bell'- Telephone Laboratories, IncorporatedJ NeW YorkQN. Y., a corporation of New York Application March 2, 1934, Serial No. 713,764 I of course, capable of other uses.
  • An object of the invention is the production of a large number of waves spaced in frequency with an economy in filtering circuits necessary for separation of thevarious wave components.
  • a further object ' is the production of a large number of waves spaced in frequency with a minimum production of spurious or unwanted frequencies.
  • a I I A feature of the present invention is a circuit structure in which the 'wavesiasfinally produced appear in a number'of separate circuits'with a frequency spacing sufficiently large .to enable them to beseparated readily: The final output waves which are close together in frequency are produced in difierent'output circuits and do not need to be separated from one another by filtering means. 'j
  • theiproblem is to produce a series of electrical waves with a spacing of 2 kilocycles beginning with-a lower frequency of 12 kilocycles and extending-,to-an upper frequency of 250 kilocycles per second,,as indicated by the final output filters 40, 41,..42, 43, etc. shown at the right-hand side of 1 the figure. It is further assumed thatthese waves are to be produced from a single originating source shown at 1 in the lower left corner of the figure, this source comprising a4 kilocycle generator of any suitable type for delivering 'a constant frequency wave.
  • the source of constant 4 kilocycle frequency waves 1 leads to a harmonic generator? which may be conveniently of the multi-vibrator type 'of circuit well known in the art and which produces in its two output circuit branches a 2 kilocycle frequency and multiples thereof.
  • Another branch from the output o f'modul'ator '7 supplies a 520 kilocycle; component to each of two filters- 8 and ;14.
  • - Filter 8 is preferably a band pass filter of. the crystal type with a highly component iseffectively isolated from all of'the I otherspresent.
  • v The filters-10tot19 which have to meet ,the mostfrigid requirements, thatg'are placed on any of the filters of the system donot nee'd'tobe as complicated as might beexpected.
  • a filter comprisingon'ecrystal in series in the circuit with ashunt arm on one or both sides of the crystal, comprising-a condenser is capable of discriminating between 520 and '522 kilocycle waves with adiscrimination of the order .of 20 or 25 decibels.
  • Each of; the modulators 20 to 29, inclusive is therefore supplied with a substantially pure'wave of asingle frequency, namely 512 kilocycles, 514-530 kilocycles, respectively.
  • the modulator 23 by way of example.
  • This modulator has appliedto it a substantially pure wave component of- 518 -kilocycles together-with thirteeri difierentfrequency components extending from 280 to 520 kilocycles tenth multiple or 20 kilocycles is selected byinclusive with a spacing of 20 kilocycles, these components being derived, as previously stated, from modulator 7. Considering only the lower sideband components resulting from the action of modulator 23, the highest of these output components is obtained by subtracting 280 from 518 kilocycles which gives 238 kilocycles.
  • the lowestof theoutput components is found by subtracting 500 from 518 kilocycles making an 18 kilocycle component. Other components between these extremes are obtained at frequency intervals of 20 kilocycles.
  • the output leads from modulator 23 are shown multipled to two filters 43 and 43, the former of which is selective to the 18 kilocycle component and the latter to the 38 kilocycle component. It will be understood that these leads are multipled to other filters similar to 43 and 43, but not shown in the drawing, these other filters being selective, respectively, to 58, 78-238 kilocycles, respectively.
  • modulator 24 has applied to it'a' 520 kilocycle component from filter 14 (in this case) and a series of waves from the output of modulator '7 comprising components 280 to 520 kilocycles with 20 kilocycle spacing.
  • the lower sideband components in the output of modulator 24 comprise, therefore, the components 20, 40, 60-240 kilocycles which appear in the output leads 34.
  • These leads are shown multipledto a 20- kilocycle'filter 44 and a 40 I kilocycle filter 44 and it will be understood that they are also multipled to other filters not shown in the drawing but selective to the other frequencies present in these leads.
  • each of the modulators 20 to 29, inclusive has applied to its input a single high frequency component and a series of lower frequency components whereby there are produ'cedin the output of each modulator a series of wave components 20 kilocycles apart.
  • the filters connected to any one modulator output branch such as 33 have a very low requirement placed upon them since they only need to separate between frequencies 20 kilocycles apart, the highest of which is 250 kilocycles. In the most severe case this represents a separation between components that are spaced apart by about of the frequencies in question, a requirement easily met by a simple and economical type of filter design.
  • 120 wave components extending from 12 to 250 kilocycles with a 2 kilocycle spacing are obtained by a circuit arrangement in which the minimum frequency separation required by thefinal output filters is 20 kilocycles.
  • the ten filters 10' to 19, inclusive, which are required to have high discrimination are few in number, representing-in the illustration given less than 10% of'the number of thefinal output filters. r w
  • the lowest input component frequency is 280 kilocycles, whereas it will be noted that the highest frequency utilized is 250 kilocycles so that no interference from the 280 kilocycle wave or a harmonic of it or any other input component is possible.
  • the method of producing a number of waves spaced in frequency comprising producing a series of waves with a greater frequency interval than that of the desired waves, producing a second series of waves of higher frequency than the first series and with the desired frequency spacing, and modulating each of the latter Waves by a plurality of the former to'produce waves of the desired frequencies.
  • the method of producing a number of waves spaced in frequency comprising producing a series of waves with a greater spacing than that of the desired waves; producing a .second series. of waves of higher frequency than'the first series and with the desired frequency spacing, separating the latter waves :into separate circuits, modulating each of the waves so separated by a plurality of waves of the first mentioned series to produce lower sideband waves of the desired frequencies, and separating .the resulting waves.
  • means to produce a first series of waves with a greater frequency spacing than that of the desired waves means to produce a second series of waves of higher frequency than the first series and with the desired frequency spacing, and means to modulate each of the latter waves with a plurality of the waves of the first series to produce resultant waves of the desired frequency and frequency spacing.
  • a plurality of modulators circuits applying to onemodulato-r a high frequency wave and a series of lower frequency waves spaced in frequency to produce resultant lower sideband Waves of the same frequency spacing but lower than said high frequency, circuits supplying to a second modulator said series of waves and a second high frequency wave spaced in frequency from said first high frequency wave by less than the spacing of said series of waves to produce resultant lower sideband waves overlapping in frequency the first mentioned lower sideband waves, and means on the output side of each modulator for selecte ing the; different resultant waves.
  • a wave producing system a master source of waves ofv given frequency, a first wave translating circuit for producing under control of'said source a certain series of waves spaced in frequency, a second wave translating circuit for producing under control of said source a sec,- ond series of waves more closely spaced and of higherfrequency than the first series, and means to modulate each of said latter waves by a pluralityof said first series of waves to produce waves having frequencies lower than either series and with the spacing of said second series.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Networks Using Active Elements (AREA)

Description

Dec. 18, 1934. w. A. MARRISON ET AL 1,985,046
ELECTRICAL WAVE PRODUCTION Filed March 2, 1934 II H H II II ll MOD.
B.P.F.
MOD.
2a,4a,sa-24a Kc. KC 37 MOD.
2s 46,66-246 wc.
MOD.
24 44,e4-244 K.C.
MOD.
IOO K.
2OK.C.
L.P. FILTE K.C. MOD.
MOD.
MOD.
20,40,617; 12o KL.
|a,as,5a 238 no.
MOD.
|s,se,5s,7e-23s K.C.
MOD.
FILTE FILTER 2.10 Kc. 12 32,52, 72- 2 2 K C- WAMARR/SO/V 4 K.C. GENERATOR INVENTORS- UM Q ATTORN V I4 34 54,74-234 K.C.
MOD.
Patented Dec. 18, 1934 UNITED STATES ELECTRICAL WAVE PaoDUc'rIoN i Warren A Marrison, Maplewood; and Larned A. Meacham Montclair, N. J., assignors to Bell'- Telephone Laboratories, IncorporatedJ NeW YorkQN. Y., a corporation of New York Application March 2, 1934, Serial No. 713,764 I of course, capable of other uses.
An object of the invention is the production of a large number of waves spaced in frequency with an economy in filtering circuits necessary for separation of thevarious wave components.
A further object 'is the production of a large number of waves spaced in frequency with a minimum production of spurious or unwanted frequencies.. a I I A feature of the present invention is a circuit structure in which the 'wavesiasfinally produced appear in a number'of separate circuits'with a frequency spacing sufficiently large .to enable them to beseparated readily: The final output waves which are close together in frequency are produced in difierent'output circuits and do not need to be separated from one another by filtering means. 'j
A more complete understanding of the invention together with its various objects and features will be had from thefollowing detailed description when read in connection with the ac-' companying drawing in which the single figure shows in block diagram the circuit structure of a system according to the invention by which a large number of waves closely spaced in frequency are produced. l
While the invention is of general application, its mode of application will be readily understood by considering a specific problem as out lined in the accompanying drawing. It isfassumed for illustrative purposes thattheiproblem is to produce a series of electrical waves with a spacing of 2 kilocycles beginning with-a lower frequency of 12 kilocycles and extending-,to-an upper frequency of 250 kilocycles per second,,as indicated by the final output filters 40, 41,..42, 43, etc. shown at the right-hand side of 1 the figure. It is further assumed thatthese waves are to be produced from a single originating source shown at 1 in the lower left corner of the figure, this source comprising a4 kilocycle generator of any suitable type for delivering 'a constant frequency wave. I
The source of constant 4 kilocycle frequency waves 1 leads to a harmonic generator? which may be conveniently of the multi-vibrator type 'of circuit well known in the art and which produces in its two output circuit branches a 2 kilocycle frequency and multiples thereof. The
5Claims. (01.250-36) Y filter 3 and impressed on the harmonicgenerator 4 which is shownafprovided with two -,output branches, one leading to harmonic generaton-E; and'delivering thereto a wave of kilocycles;
the fourth multiple of which is supplied to one input branch ofmodulator 7. The otherbranch from, harmonic generator 4 delivers multiples of 20 kilocycles up to andincluding kilo cycles throughthe low pass filter 6 to the second input branch of the modulator {7 Modulator 7 produces upper and lower sidebands resulting from the modulation of the 400 kilocycle-component with the 20, 40-120 kilocycle components from filter 6, these sidebands representing com ponents extending; from 280 to 52 0 kilocycles with a 20'kilocycle spacing between components.
The output of this modulator -'7 is;supplied; in
multiple to each of the ten modulators 20 to 29 inclusive, 9 v
Another branch from the output o f'modul'ator '7 supplies a 520 kilocycle; component to each of two filters- 8 and ;14.- Filter 8 is preferably a band pass filter of. the crystal type with a highly component iseffectively isolated from all of'the I otherspresent. v ,The filters-10tot19 which have to meet ,the mostfrigid requirements, thatg'are placed on any of the filters of the system donot nee'd'tobe as complicated as might beexpected. Forexamplejapplicants-have found that a filter comprisingon'ecrystal in series in the circuit with ashunt arm on one or both sides of the crystal, comprising-a condenser, is capable of discriminating between 520 and '522 kilocycle waves with adiscrimination of the order .of 20 or 25 decibels. Each of; the modulators 20 to 29, inclusive, is therefore supplied with a substantially pure'wave of asingle frequency, namely 512 kilocycles, 514-530 kilocycles, respectively. Consider now the modulator 23,, by way of example. This modulator has appliedto it a substantially pure wave component of- 518 -kilocycles together-with thirteeri difierentfrequency components extending from 280 to 520 kilocycles tenth multiple or 20 kilocycles is selected byinclusive with a spacing of 20 kilocycles, these components being derived, as previously stated, from modulator 7. Considering only the lower sideband components resulting from the action of modulator 23, the highest of these output components is obtained by subtracting 280 from 518 kilocycles which gives 238 kilocycles. The lowestof theoutput components (neglecting the 2 kilocycle component which is not used) is found by subtracting 500 from 518 kilocycles making an 18 kilocycle component. Other components between these extremes are obtained at frequency intervals of 20 kilocycles. The output leads from modulator 23 are shown multipled to two filters 43 and 43, the former of which is selective to the 18 kilocycle component and the latter to the 38 kilocycle component. It will be understood that these leads are multipled to other filters similar to 43 and 43, but not shown in the drawing, these other filters being selective, respectively, to 58, 78-238 kilocycles, respectively. In similar manner modulator 24 has applied to it'a' 520 kilocycle component from filter 14 (in this case) and a series of waves from the output of modulator '7 comprising components 280 to 520 kilocycles with 20 kilocycle spacing. The lower sideband components in the output of modulator 24 comprise, therefore, the components 20, 40, 60-240 kilocycles which appear in the output leads 34. These leads are shown multipledto a 20- kilocycle'filter 44 and a 40 I kilocycle filter 44 and it will be understood that they are also multipled to other filters not shown in the drawing but selective to the other frequencies present in these leads.
In similar manner each of the modulators 20 to 29, inclusive, has applied to its input a single high frequency component and a series of lower frequency components whereby there are produ'cedin the output of each modulator a series of wave components 20 kilocycles apart. It will benoted that the filters connected to any one modulator output branch such as 33 have a very low requirement placed upon them since they only need to separate between frequencies 20 kilocycles apart, the highest of which is 250 kilocycles. In the most severe case this represents a separation between components that are spaced apart by about of the frequencies in question, a requirement easily met by a simple and economical type of filter design. Thus, in the example given 120 wave components extending from 12 to 250 kilocycles with a 2 kilocycle spacing are obtained by a circuit arrangement in which the minimum frequency separation required by thefinal output filters is 20 kilocycles.
The ten filters 10' to 19, inclusive, which are required to have high discrimination are few in number, representing-in the illustration given less than 10% of'the number of thefinal output filters. r w By utilizing only the lower frequency sideband resulting from each of the modulators 20 to 29, inclusive, all interference from harmonics of the input waves is avoided. For example, the lowest input component frequency is 280 kilocycles, whereas it will be noted that the highest frequency utilized is 250 kilocycles so that no interference from the 280 kilocycle wave or a harmonic of it or any other input component is possible.
It will be obvious from the example that has been given that the principle of v the invention can be extended to cover widely different frequencies and arrangements from those illustrated and described. The magnitudes given are typical and practicable for supplying carrier waves to an actual carrier signaling system such as a carrier telephone system, but it will be understood that the specific frequencies mentioned and also the actual number of filters, modulators, etc. to be employed in any given system can be varied widely to suit requirements and the values that have been given are to be taken as illustrative and not as limiting.
What is claimed is:
1. The method of producing a number of waves spaced in frequency comprising producing a series of waves with a greater frequency interval than that of the desired waves, producing a second series of waves of higher frequency than the first series and with the desired frequency spacing, and modulating each of the latter Waves by a plurality of the former to'produce waves of the desired frequencies.
2. The method of producing a number of waves spaced in frequency comprising producing a series of waves with a greater spacing than that of the desired waves; producing a .second series. of waves of higher frequency than'the first series and with the desired frequency spacing, separating the latter waves :into separate circuits, modulating each of the waves so separated by a plurality of waves of the first mentioned series to produce lower sideband waves of the desired frequencies, and separating .the resulting waves.
3. In a system forproducing waves of spaced frequencies, means to produce a first series of waves with a greater frequency spacing than that of the desired waves, means to produce a second series of waves of higher frequency than the first series and with the desired frequency spacing, and means to modulate each of the latter waves with a plurality of the waves of the first series to produce resultant waves of the desired frequency and frequency spacing.
4. In a wave producing system, a plurality of modulators, circuits applying to onemodulato-r a high frequency wave and a series of lower frequency waves spaced in frequency to produce resultant lower sideband Waves of the same frequency spacing but lower than said high frequency, circuits supplying to a second modulator said series of waves and a second high frequency wave spaced in frequency from said first high frequency wave by less than the spacing of said series of waves to produce resultant lower sideband waves overlapping in frequency the first mentioned lower sideband waves, and means on the output side of each modulator for selecte ing the; different resultant waves.
am a wave producing system, a master source of waves ofv given frequency, a first wave translating circuit for producing under control of'said source a certain series of waves spaced in frequency, a second wave translating circuit for producing under control of said source a sec,- ond series of waves more closely spaced and of higherfrequency than the first series, and means to modulate each of said latter waves by a pluralityof said first series of waves to produce waves having frequencies lower than either series and with the spacing of said second series.
7 WARREN A. {MARRISON LARNED .A. MEACHAM.
US713764A 1934-03-02 1934-03-02 Electrical wave production Expired - Lifetime US1985046A (en)

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2418568A (en) * 1944-04-11 1947-04-08 Hewlett Packard Co Frequency divider
US2433343A (en) * 1942-03-12 1947-12-30 Int Standard Electric Corp Multichannel electrical communication system
US2507317A (en) * 1944-09-23 1950-05-09 Philco Corp Method and apparatus for synchronizing oscillators
US2513493A (en) * 1945-09-17 1950-07-04 Honeywell Regulator Co Aircraft control system
US2541320A (en) * 1948-04-23 1951-02-13 Bell Telephone Labor Inc Multifrequency generator
US2602836A (en) * 1949-10-08 1952-07-08 Ohmega Lab Instantaneous frequency analyzer
US2607851A (en) * 1947-11-18 1952-08-19 Bell Telephone Labor Inc Mop-up equalizer
US2760074A (en) * 1951-12-20 1956-08-21 Itt Frequency generator
US2879387A (en) * 1953-11-25 1959-03-24 Leonard R Kahn Multi-channel phase locked tone converter
US3984769A (en) * 1956-07-26 1976-10-05 American Standard, Inc. Mixed-base intercept receiver

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2433343A (en) * 1942-03-12 1947-12-30 Int Standard Electric Corp Multichannel electrical communication system
US2418568A (en) * 1944-04-11 1947-04-08 Hewlett Packard Co Frequency divider
US2507317A (en) * 1944-09-23 1950-05-09 Philco Corp Method and apparatus for synchronizing oscillators
US2513493A (en) * 1945-09-17 1950-07-04 Honeywell Regulator Co Aircraft control system
US2607851A (en) * 1947-11-18 1952-08-19 Bell Telephone Labor Inc Mop-up equalizer
US2541320A (en) * 1948-04-23 1951-02-13 Bell Telephone Labor Inc Multifrequency generator
US2602836A (en) * 1949-10-08 1952-07-08 Ohmega Lab Instantaneous frequency analyzer
US2760074A (en) * 1951-12-20 1956-08-21 Itt Frequency generator
US2879387A (en) * 1953-11-25 1959-03-24 Leonard R Kahn Multi-channel phase locked tone converter
US3984769A (en) * 1956-07-26 1976-10-05 American Standard, Inc. Mixed-base intercept receiver

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FR786456A (en) 1935-09-03

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