GB553428A - Circuit for generating and modulating carrier waves - Google Patents
Circuit for generating and modulating carrier wavesInfo
- Publication number
- GB553428A GB553428A GB5891/42A GB589142A GB553428A GB 553428 A GB553428 A GB 553428A GB 5891/42 A GB5891/42 A GB 5891/42A GB 589142 A GB589142 A GB 589142A GB 553428 A GB553428 A GB 553428A
- Authority
- GB
- United Kingdom
- Prior art keywords
- crystal
- valve
- circuit
- transformer
- output
- 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
Links
- 239000013078 crystal Substances 0.000 abstract 6
- 230000010355 oscillation Effects 0.000 abstract 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03C—MODULATION
- H03C1/00—Amplitude modulation
- H03C1/52—Modulators in which carrier or one sideband is wholly or partially suppressed
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
- H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
- H03B5/30—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element being electromechanical resonator
- H03B5/32—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element being electromechanical resonator being a piezoelectric resonator
- H03B5/34—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element being electromechanical resonator being a piezoelectric resonator active element in amplifier being vacuum tube
Landscapes
- Amplitude Modulation (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
553,428. Valve generating and modulating circuits. STANDARD TELEPHONES & CABLES, Ltd. May 1, 1942, No. 5891. Convention date, May 3, 1941. [Class 40 (v)] In a combined valve modulator and generator circuit, a piezo-electric crystal functions to stabilize the generator frequency and to suppress the unmodulated carrier. As shown, the crystal 2 has its lower electrode 8 earthed, and its two upper electrodes 7, 9 connected respectively to the plate and to the grid 22 of a valve 20, which generates oscillations at the series-resonant frequency of the crystal. Modulation is applied through a transformer 3 to the inner grid of the valve 20, giving a modulated output through the transformer 6. From this output, the unmodulated carrier is suppressed by the short-circuiting effect of the crystal electrodes 7, 8. One of the sidebands may also be suppressed by a filter 28. The modulated output may be fed through a condenser 26 to a rectifying diode 14. The diode load impedance Z, is high at voice frequencies and as it is included in the circuit of the inner grid, it gives a negative feed-back effect to reduce distortion. An impedance Z 2 between the valve plate and the crystal, and a further network Z 3 between the diode anode 14 and earth, offer high impedance at the carrier and side band frequencies. In a simpler circuit, Fig. 1 (not shown), the diode anode is connected through resistances both to the secondary of the output transformer 6 and to the electrode 9 of the crystal, and the network Z 2 is omitted.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US391676A US2298460A (en) | 1941-05-03 | 1941-05-03 | Modulated oscillator |
Publications (1)
Publication Number | Publication Date |
---|---|
GB553428A true GB553428A (en) | 1943-05-20 |
Family
ID=23547521
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB5891/42A Expired GB553428A (en) | 1941-05-03 | 1942-05-01 | Circuit for generating and modulating carrier waves |
Country Status (2)
Country | Link |
---|---|
US (1) | US2298460A (en) |
GB (1) | GB553428A (en) |
-
1941
- 1941-05-03 US US391676A patent/US2298460A/en not_active Expired - Lifetime
-
1942
- 1942-05-01 GB GB5891/42A patent/GB553428A/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
US2298460A (en) | 1942-10-13 |
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