US2787704A - Constant band-width input stage with high q antenna - Google Patents

Constant band-width input stage with high q antenna Download PDF

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Publication number
US2787704A
US2787704A US502370A US50237055A US2787704A US 2787704 A US2787704 A US 2787704A US 502370 A US502370 A US 502370A US 50237055 A US50237055 A US 50237055A US 2787704 A US2787704 A US 2787704A
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US
United States
Prior art keywords
winding
frequency
circuit
aerial
antenna
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
US502370A
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English (en)
Inventor
Boelens Willem Wigger
Tap Jan Willem
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.)
US Philips Corp
North American Philips Co Inc
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US Philips Corp
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 US Philips Corp filed Critical US Philips Corp
Application granted granted Critical
Publication of US2787704A publication Critical patent/US2787704A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J3/00—Continuous tuning
    • H03J3/02—Details
    • H03J3/06—Arrangements for obtaining constant bandwidth or gain throughout tuning range or ranges

Definitions

  • the invention relates to a receiving apparatus comprising a rod aerial, in which the winding of the rod aerial is included in an input circuit of a high-frequency amplifier tuned to the signal to be received.
  • rod aerial is to be understood to mean an aerial comprising a usually rotatable rod of ferromagnetic material, on which a Winding is provided.
  • the ferromagnetic material may, in this case, be in general a known ferrite having a high permeability and a low specific resistance.
  • the disagreeable effect is produced that owing to the high-Q of the input circuit including the winding of the rod aerial, the circuit band-width is so narrow that the high sidebands are attenuated to a greater extent, so that the sound reproduction becomes inadmissibly dull.
  • a means to remedy this effect consists in that the damping of the circuit is increased, for example by including a resistor. This, however, has the disadvantage that the capturing power of the rod is too strongly reduced and the signalnoise ratio is diminished.
  • the invention has for its object to obviate the said disadvantage of the input circuits including a rod aerial, without an additional reduction of the capturing power of the rod and of the signal-noise ratio.
  • the invention consists in that in an apparatus of the kind described above provision is made of means to provide a negative feed-back which decreases at an increase in signal frequency between the output circuit of the amplifier and the input circuit.
  • the band-width of the circuit is increased to a value commensurate with the full band-width of the signal. Since the negative feedback is operative both for the band-width of the signal and for the noise, the signal-noise ratio associated with a high circuit quality is maintained.
  • the band-Width of the circuit is increased and is comparable to that of a circuit of low-Q.
  • a winding is provided in series with the aerial winding included in the input circuit, this winding being coupled with a third winding, which is connected in parallel with a capacitor, the parallel combination being tuned to a frequency which is lower than the lowest frequency to be received, this combination forming part of the output circuit of a high-frequency amplifying tube.
  • the said parallel combination is preferably connected between the cathode of the tube and earth,
  • the drawing shows the circuit arrangement of the input section of a receiving apparatus according to the invention as far as it is required for a good understanding of the invention. 7
  • reference numeral 1 designates the ferrite rod of the aerial, to whichthe aerial winding 2 is applied.
  • the high-frequency oscillations captured by the rod with the winding are amplified in a pentode 3, the amplified oscillations being obtained from the output impedance 4.
  • the parallel combination of the resistor 5 and the capacitor 6 in the lead from cathode to earth serves to obtain a particular bias voltage at the control-grid.
  • the series combination of a coil 7 and a capacitor 10 to the common point of which an external aerial 13 can be connected.
  • the winding 7 is coupled, in accordance with the invention, with a winding 8, in parallel with which a capacitor 9 is connected. This parallel combination is also included in the lead from the cathode of the tube 3 to earth.
  • the tuning of the input circuit is carried out by means of the capacitor 12.
  • a grid resistor 11 is connected in parallel with the coupling capacitor 10.
  • the windings 7 and i5 produce a negative feed-back. Owing to the capacitor 9 it is ensured that this negative feed-back decreases at an increase in frequency.
  • the parallel combination 8, 9 is tuned to this end to a frequency lower than the lowest signal frequency to be received, for example to a frequency of kc./s.
  • the anode current of the tube 3 flows from the positive terminal of the supply, through the impedance 4, the tube 3, the parallel combination 5, 6 and the parallel combination 8, 9 to the negative terminal of the supply connected to earth. If the signal frequency increases, a smaller part of the alternating anode current Will flow through the coil 8, so that the negative feedback decreases. At comparatively high frequencies the effect of the negative feed-back is substantially equal to zero.
  • a receiving apparatus comprising a high-frequency amplifier having an input circuit tuned to a signal to be received and having a signal output circuit, a rod aerial composed of a core of ferromagnetic material and a winding positioned on said core, said winding being connected electrically in said input circuit, a negative feedback circuit connected between said output circuit and said input circuit, and frequency-discriminating means connected in said feedback circuit to provide a relatively decreased amount of feedback for a relative increase in the frequency of said signal.

Landscapes

  • Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
  • Circuits Of Receivers In General (AREA)
US502370A 1954-04-21 1955-04-19 Constant band-width input stage with high q antenna Expired - Lifetime US2787704A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL768423X 1954-04-21

Publications (1)

Publication Number Publication Date
US2787704A true US2787704A (en) 1957-04-02

Family

ID=19827682

Family Applications (1)

Application Number Title Priority Date Filing Date
US502370A Expired - Lifetime US2787704A (en) 1954-04-21 1955-04-19 Constant band-width input stage with high q antenna

Country Status (4)

Country Link
US (1) US2787704A (enrdf_load_stackoverflow)
BE (1) BE537486A (enrdf_load_stackoverflow)
FR (1) FR1133386A (enrdf_load_stackoverflow)
GB (1) GB768423A (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1282744B (de) * 1965-07-02 1968-11-14 Csf Empfangs-Rahmenantenne
US4103241A (en) * 1975-08-11 1978-07-25 Reach Electronics, Inc. Rf amplifier and antenna
WO1980002782A1 (en) * 1979-05-25 1980-12-11 Tracor Antenna low-noise q spoiling circuit
EP2541680A1 (en) 2011-06-29 2013-01-02 Roke Manor Research Limited Reduced Q low frequency antenna

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2351934A (en) * 1944-06-20 Selectivity apparatus
US2555906A (en) * 1940-01-31 1951-06-05 Hartford Nat Bank & Trust Co Tunable amplifier having a predetermined band-pass characteristic throughout its range
US2603723A (en) * 1947-06-03 1952-07-15 Philco Corp High-frequency amplifier circuit
US2641704A (en) * 1950-08-03 1953-06-09 Rca Corp High-inductance loop antenna and system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2351934A (en) * 1944-06-20 Selectivity apparatus
US2555906A (en) * 1940-01-31 1951-06-05 Hartford Nat Bank & Trust Co Tunable amplifier having a predetermined band-pass characteristic throughout its range
US2603723A (en) * 1947-06-03 1952-07-15 Philco Corp High-frequency amplifier circuit
US2641704A (en) * 1950-08-03 1953-06-09 Rca Corp High-inductance loop antenna and system

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1282744B (de) * 1965-07-02 1968-11-14 Csf Empfangs-Rahmenantenne
US4103241A (en) * 1975-08-11 1978-07-25 Reach Electronics, Inc. Rf amplifier and antenna
WO1980002782A1 (en) * 1979-05-25 1980-12-11 Tracor Antenna low-noise q spoiling circuit
EP0029027A4 (en) * 1979-05-25 1981-08-27 Tracor LOW NOISE Q DETERIORATION CIRCUIT OF AN ANTENNA.
US4314378A (en) * 1979-05-25 1982-02-02 Tractor, Inc. Antenna low-noise Q spoiling circuit
EP2541680A1 (en) 2011-06-29 2013-01-02 Roke Manor Research Limited Reduced Q low frequency antenna

Also Published As

Publication number Publication date
FR1133386A (fr) 1957-03-26
GB768423A (en) 1957-02-13
BE537486A (enrdf_load_stackoverflow)

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