GB660192A - Improvements in or relating to radio receivers - Google Patents
Improvements in or relating to radio receiversInfo
- Publication number
- GB660192A GB660192A GB426248A GB426248A GB660192A GB 660192 A GB660192 A GB 660192A GB 426248 A GB426248 A GB 426248A GB 426248 A GB426248 A GB 426248A GB 660192 A GB660192 A GB 660192A
- Authority
- GB
- United Kingdom
- Prior art keywords
- pulse
- resistance
- low
- noise
- overswing
- 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
- 230000004048 modification Effects 0.000 abstract 2
- 238000012986 modification Methods 0.000 abstract 2
- 230000002238 attenuated effect Effects 0.000 abstract 1
- 238000007493 shaping process Methods 0.000 abstract 1
- 238000001228 spectrum Methods 0.000 abstract 1
- 230000003068 static effect Effects 0.000 abstract 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers
- H03G3/20—Automatic control
- H03G3/30—Automatic control in amplifiers having semiconductor devices
- H03G3/34—Muting amplifier when no signal is present or when only weak signals are present, or caused by the presence of noise signals, e.g. squelch systems
- H03G3/345—Muting during a short period of time when noise pulses are detected, i.e. blanking
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G11/00—Limiting amplitude; Limiting rate of change of amplitude ; Clipping in general
- H03G11/002—Limiting amplitude; Limiting rate of change of amplitude ; Clipping in general without controlling loop
Landscapes
- Noise Elimination (AREA)
Abstract
660,192. Radio receiving circuits. STANDARD TELEPHONES & CABLES, Ltd. Feb. 11, 1949 [Feb. 13, 1948], No. 4262/48. Class 40 (v). In a receiver having a band-width greater than necessary for the modulation received, filter and pulse-shaping means are used to derive the high or low-frequency components of noise pulses and counteract static. A demodulated wave with superimposed noise pulse, as shown (Fig. 1a), may be applied to a valve 8 (Fig. 3), with a high-pass filter 16 as cathode load, terminating with a resistance 19 and diode 17. The diode input takes the form shown in Fig. 1 (b), its output across cathode load resistance 18 eliminating the negative overswing to produce the pulse (c). The negative overswing contains low-frequency components of the noise pulse frequency spectrum which cancel corresponding low-frequency components in the positive swing. Removal of the negative overswing therefore leaves the pulse (c) containing both low and high frequencies of the original pulse. On combining the latter developed across resistance 18, therefore with a phaseinverted output of the original demodulated wave developed across the anode load 12 of the valve 8 and suitably attenuated by a tapped potentiometer 21 in series with the resistance 18, the tapped output at 22 of the potentiometer is free from noise pulse. In a modification (Fig. 4, not shown), the high-pass filter comprises simply a condenser 23, and a diode 24 clipping the base of the pulse replaces the resistance 19. In a further modification (Fig. 7, not shown), the valve 8 is dispensed with, a condenser 30 acts as a high-pass filter and the diode 17 is reversed so that across its anode load resistance 18 only the negative overswing, containing only low-frequency components of the noise pulse reversed in phase, is produced. On combination with a shunt demodulation output across a tapped potentiometer 21 the low-frequency noise components are eliminated. A final shunt condenser 34 eliminates the high-frequency noise components. Contact rectifiers may replace the diodes. Specification 641,211 is referred to.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB426248A GB660192A (en) | 1948-02-13 | 1948-02-13 | Improvements in or relating to radio receivers |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB426248A GB660192A (en) | 1948-02-13 | 1948-02-13 | Improvements in or relating to radio receivers |
Publications (1)
Publication Number | Publication Date |
---|---|
GB660192A true GB660192A (en) | 1951-10-31 |
Family
ID=9773793
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB426248A Expired GB660192A (en) | 1948-02-13 | 1948-02-13 | Improvements in or relating to radio receivers |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB660192A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2837662A (en) * | 1955-09-29 | 1958-06-03 | Honeywell Regulator Co | Measuring and control apparatus |
US2972677A (en) * | 1957-12-04 | 1961-02-21 | Itt | Interference detecting circuit |
US3497818A (en) * | 1965-10-22 | 1970-02-24 | Int Standard Electric Corp | Circuit for centering pcm zero level |
CN109391875A (en) * | 2018-10-23 | 2019-02-26 | 珠海格力智能装备有限公司 | Audio debugging method and device, storage medium and processor |
-
1948
- 1948-02-13 GB GB426248A patent/GB660192A/en not_active Expired
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2837662A (en) * | 1955-09-29 | 1958-06-03 | Honeywell Regulator Co | Measuring and control apparatus |
US2972677A (en) * | 1957-12-04 | 1961-02-21 | Itt | Interference detecting circuit |
US3497818A (en) * | 1965-10-22 | 1970-02-24 | Int Standard Electric Corp | Circuit for centering pcm zero level |
CN109391875A (en) * | 2018-10-23 | 2019-02-26 | 珠海格力智能装备有限公司 | Audio debugging method and device, storage medium and processor |
CN109391875B (en) * | 2018-10-23 | 2021-03-26 | 珠海格力智能装备有限公司 | Audio debugging method and device, storage medium and processor |
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