US2125953A - Receiver of telephonic or telegraphic signals - Google Patents

Receiver of telephonic or telegraphic signals Download PDF

Info

Publication number
US2125953A
US2125953A US145196A US14519637A US2125953A US 2125953 A US2125953 A US 2125953A US 145196 A US145196 A US 145196A US 14519637 A US14519637 A US 14519637A US 2125953 A US2125953 A US 2125953A
Authority
US
United States
Prior art keywords
signals
circuit
receiver
rectifier
amplifier
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US145196A
Other languages
English (en)
Inventor
Prochnow Rudolf
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Telefunken AG
Original Assignee
Telefunken AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Telefunken AG filed Critical Telefunken AG
Application granted granted Critical
Publication of US2125953A publication Critical patent/US2125953A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
    • H04M11/06—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/02—Amplitude-modulated carrier systems, e.g. using on-off keying; Single sideband or vestigial sideband modulation
    • H04L27/06—Demodulator circuits; Receiver circuits
    • H04L27/063—Superheterodyne receivers

Definitions

  • the general aim to simplify the operation of commercial receiver apparatus involves the problem to make the change from reception of telegraphic signals to telephonic signal reception automatic. It has been suggested in the prior art to utilize for the said change the direct current component resulting from the rectification of the incoming radio frequency signals by feeding the direct current voltage produced by the carrier wave to a time-lag relay which responds only to impulses of long duration. Inasmuch as in telegraphic work the direct current component varies at the rhythm and rate of the signals between, zero and maximum, whereas it is constant in the reception of telephonic signals the relay responds only to telephone signal reception, and disconnects the heterodyne employed in the reception of telegraphic signals.
  • the change is a function of the telegraphing speed. If the signals are of long duration it may happen that the automatic device disconnects the heterodyne although no modulated signals (telephony) are present. This is due to the fact that the time-lag of the relay cannot be pushed to any desired limit. Moreover, in. the case of transmitters comprising means insuring automatic blocking of the carrier between words (quiescent aerial radiation) the time lapses of telephonic signals are liable to have only the length of a somewhat long telegraphic signal. It will be seen therefrom that the change is apt to be attended with inaccuracies and defects in systems of the said sort.
  • a receiver for selective reception of telephonic and nonmusical telegraphic signals is so designed that automatic change in connections is accomplished by the aid of rectified telephony modulation.
  • Modulation must be derived from the receiver, of course, at a point where the heterodyne frequency required for the reception of telegraphic signa1$ has not yet been added. This will be feasible only if reception of telegraphic signals is effected by sonic (audio frequency) modulation of the first heterodyne of a superheterodyne receiver apparatus. However, it is possible in this case to filter this note so that the change mechanism will not respondto the said modulation frequency.v
  • a circuit I tuned to the intermediate frequency, and furthermore, an audio frequency coupler transformer 2. If the grid biasing voltage for IE! is properly chosen, this stage acts as a radio frequency amplifier and a rectifier.
  • the second heterodyne oscillator tube 20 In coupling relation' with the tuning circuit l is the second heterodyne oscillator tube 20 which is fed with plate potential by way of the resting contact 22 of magnet relay 3. Mixing of the incoming wave, 1. e., the intermediate frequency output of III, and the auxiliary wave supplied by 20, is effected in the rectifier circuit 4.
  • the heterodyne voltage transformed in. the circuit is so chosen that it will not contribute any appreciable amount to thevolume control potential.
  • the regulation voltage is a function of the amplitude of the receiver input potential.
  • Such telegraphic signals as may be received produce, when beat with oscillations from the second heterodyne 2i), beat notes which are fed by way of the audio frequency amplifier 30 to the headphones.
  • an alternating voltage will exist only in case of telephonic reception.
  • This voltage is then amplified by audio frequency amplifier i0, is then rectified by full-wave rectifier 50 and then fed to the relay 3.
  • the second heterodyne 20 can be disconnected by the relay only in case of telephony signals.
  • the receiver is always ready to receive telegraphic signals, and it is changed over in case modulated signals are coming in.
  • the relay is to be dispensed with as shown in Fig. 2.
  • the alternating potential furnished from the audio frequency amplifier is rectified and is used as a counter-voltage for a glow tube 8.
  • the output of 50 supplies voltage to a resistor 6!] in the direct current circuit of 8.
  • the resistor 60 is poled to oppose the potential supplied by the direct current circuit to 8.
  • the glow tube circuit is a voltage divider for the screen grid potential of the second heterodyne 20 and supplies the plate potential also.
  • amplifier stage 40 in a reflex circuit scheme may be combined with the preceding stages of the receiver equipment. make sure that this tube will not be afiected by the automatic volume control regulation, other wise it will not operate to cause the receiver to respond to telegraphy except in the presence of telephony.
  • FIG. 3 Another circuit organization is shown in Fig. 3.
  • the voltage arising across the coupler 2 in the presence of telephonic signals is rectified and is used in the form of a negative grid bias for the power tube 30 of the audio frequency amplifier;
  • the plate circuit of the said power tube moreover contains, in addition to the output coupler 6, also a relay 3 which responds to'a change of the plate current of about 2 milliamps.
  • the power tube 30 operates only with a very low negative biasing voltage. This is readily possible since distortions are immaterial.
  • the powertube will be more strongly biased so that the incidentally caused change in the plate current disconnects the plate circuit of the second heterodyne 20 bythe action of relay 3.
  • the incoming signals moreover, must have a certain amplitude in order that the automatic device may be operated. It will be readily understood that unduly feeble signals will lead to failure of the automatic device so much less frequently, the steeper the regulation characteristic of the volume control means.
  • a wave amplifier and rectifier means for impressing said signals on said amplifier, a utilization circuit responsive to wave energy coupled to the output of said rectifier, a local oscillator coupled to said wave amplifier and rectifier and normally'operative to impress beating oscillations thereon when continuous wave energy is impressed on said amplifier, the resulting beat note being impressed on said utilization circuit, and additional means coupled to' said' rectifier and associated with said oscillator for rendering said oscillator inoperative when signal modulated waves are impressed on said'wave amplifying means.
  • wave receiving amplifying and demodulating means of the heterodyne type having an'input on which the wave energy is impressedand an output from which intermediate All that is'necessary is to frequency energy is derived, a'rectifier having an input coupled to said output, said rectifier having an.
  • an amplifier circuit having input electrodes and having output electrodes coupled to a "utilization circuit, a second rectifier coupling the input of said amplifier to the output of said first rectifier, a local oscillator coupled to said first rectifier to impress thereon oscillations to be beat with the intermediate frequency wave energy when the received wave is modulated by nonmusical telegraphy signals, said oscillator being normally operative, and additional rectifying means excited by energy from the output of said first rectifier for rendering said oscillator inoperative when said received wave energy is modulated by telephony signals.
  • a demodulator of the heterodyne type' including a source of' oscillations anda first detector excited by received wave energy and by oscillations from said source of oscillators, means for deriving from said detector the beat frequency produced by beating said received wave energy with said oscillations, a beat frequency amplifier tube having input and output electrodes, means for impressing said beat frequency on said input electrodes, means for biasing the electrodes of said tube to produce plate rectification in said tube, an output circuit connected with said output electrodes, a utilization circuit coupled by a rectifier to said output circuit, an additional rectifier of the full wave type having input electrodes coupled to said output circuit and having output electrodes connected in a relay circuit, an additional oscillator coupled to said output circuit to supply oscillations thereto, and means connecting said relay with a circuit of said additional oscillator to render'the same inoperative when said received wave energy is modulated by telephony signals.
  • a local oscillator a first detector, means for impressing oscillations from said oscillator on said first detector and wave energy to be demodulated on said first detector, an output circuit coupled with said first detector, said output circuit being responsive to the beat frequency between said wave energy and said oscillations from said local oscillator, a beat frequency amplifier and rectifier of the electron dischargetube type having a control grid coupled with said output circuit and having an anode connected in an alternating current output circuit, means for biasing the electrodes of said discharge tube to produce plate rectification therein, a utilization circuit, an electron discharge tube amplifier having an anode coupled to said utilization circuit and having a control electrode, a rectifier coupling said controlling electrode to said second named output circuit, means in said second named output circuit responsive only to current components resulting from the rectification of wave energy modulated by telephony signals in said amplifier and rectifier, a third rectifier coupling said last named circuit to the

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Circuits Of Receivers In General (AREA)
US145196A 1936-03-16 1937-05-28 Receiver of telephonic or telegraphic signals Expired - Lifetime US2125953A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2125953X 1936-03-16

Publications (1)

Publication Number Publication Date
US2125953A true US2125953A (en) 1938-08-09

Family

ID=7986172

Family Applications (1)

Application Number Title Priority Date Filing Date
US145196A Expired - Lifetime US2125953A (en) 1936-03-16 1937-05-28 Receiver of telephonic or telegraphic signals

Country Status (2)

Country Link
US (1) US2125953A (enrdf_load_stackoverflow)
NL (1) NL47314C (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2451916A (en) * 1946-09-07 1948-10-19 Press Wireless Inc Radio telegraph receiving system
US2455191A (en) * 1943-07-30 1948-11-30 Mullard Radio Valve Co Ltd Radio wave detector system
US2501091A (en) * 1946-06-26 1950-03-21 Gen Railway Signal Co Station selective radio communication system
US2516937A (en) * 1946-04-19 1950-08-01 Standard Telephones Cables Ltd Receiver circuit
US2532450A (en) * 1945-07-20 1950-12-05 Cornell Dubilier Electric Pulse reception system
US3281693A (en) * 1962-12-28 1966-10-25 Bell Lab Inc Voice frequency receiver for detecting out-of-band tone signals

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2455191A (en) * 1943-07-30 1948-11-30 Mullard Radio Valve Co Ltd Radio wave detector system
US2532450A (en) * 1945-07-20 1950-12-05 Cornell Dubilier Electric Pulse reception system
US2516937A (en) * 1946-04-19 1950-08-01 Standard Telephones Cables Ltd Receiver circuit
US2501091A (en) * 1946-06-26 1950-03-21 Gen Railway Signal Co Station selective radio communication system
US2451916A (en) * 1946-09-07 1948-10-19 Press Wireless Inc Radio telegraph receiving system
US3281693A (en) * 1962-12-28 1966-10-25 Bell Lab Inc Voice frequency receiver for detecting out-of-band tone signals

Also Published As

Publication number Publication date
NL47314C (enrdf_load_stackoverflow)

Similar Documents

Publication Publication Date Title
US2175270A (en) Reduction of noise
US2147595A (en) Ultra high frequency transceiver
US2125953A (en) Receiver of telephonic or telegraphic signals
US2431167A (en) Radio alarm and two-way telephone system
US2024138A (en) Radio signaling system
US2491809A (en) Radio receiver
US2245685A (en) Automatic frequency control system
US2103878A (en) Selective radio receiving system
US2420518A (en) Power reduction circuit for radio receivers
US2264724A (en) Receiver for frequency or phase modulated oscillations
US2346545A (en) Electron discharge device circuit
US2341325A (en) Diode rectifier circuit
US2101549A (en) Silencing circuits for radio receivers
US2312374A (en) High frequency system
US2259906A (en) Automatic gain control circuit
US1999176A (en) Method and means for signaling by frequency fluctuation
US2554847A (en) Telegraph mark-hold circuit
US1709062A (en) Method of and apparatus for amplification at different frequencies
US2094625A (en) Selective radio receiving system
US2533803A (en) Audio controlled limiter
US2531505A (en) Noise suppression means for communication receiving apparatus
US2327866A (en) Modulator
US2806136A (en) Controlled modulation circuit
US2069837A (en) Automatic gain control circuits
US2047653A (en) Detector-oscillator circuit