GB681023A - Improvements in or relating to automatic level control devices for electric carrier current communication systems - Google Patents
Improvements in or relating to automatic level control devices for electric carrier current communication systemsInfo
- Publication number
- GB681023A GB681023A GB4969/50A GB496950A GB681023A GB 681023 A GB681023 A GB 681023A GB 4969/50 A GB4969/50 A GB 4969/50A GB 496950 A GB496950 A GB 496950A GB 681023 A GB681023 A GB 681023A
- Authority
- GB
- United Kingdom
- Prior art keywords
- pilot
- rectifier
- circuit
- output
- oscillator
- 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
- 230000010355 oscillation Effects 0.000 abstract 4
- 230000033228 biological regulation Effects 0.000 abstract 2
- 230000005540 biological transmission Effects 0.000 abstract 1
- 230000007423 decrease Effects 0.000 abstract 1
- 230000003247 decreasing effect Effects 0.000 abstract 1
- 230000000694 effects Effects 0.000 abstract 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B3/00—Line transmission systems
- H04B3/02—Details
- H04B3/04—Control of transmission; Equalising
- H04B3/10—Control of transmission; Equalising by pilot signal
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
- H03L5/00—Automatic control of voltage, current, or power
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Control Of Amplification And Gain Control (AREA)
Abstract
681,023. Automatic volume control. STANDARD TELEPHONES & CABLES, Ltd. Feb. 27, 1950, No. 4969/50. Class 40 (iv). [Also in Group XL (c)] In a pilot-controlled gain regulation system for a carrier communication circuit, of the type in which the rectified pilot controls the output amplitude of an oscillator used to effect the gain regulation, there is provided rectified reaction for the oscillator to limit the oscillation amplitude and a bias circuit for the pilot rectifier so that it produces a rectified voltage only when the pilot amplitude exceeds a given value. In the circuit shown, the oscillator output is applied to the heater of a thermistor 9 controlling an attenuator or an equalizer in the communication circuit. The pilot is applied to terminals 1, 2, amplified by a high impedance valve 3 and passed to a rectifier circuit 4, 5 which is biased by means of a current derived from a high resistance 28. For low pilot levels the rectifier 5 is effectively short-circuited by rectifier 4, but for higher levels the current drawn by valve 3 exceeds the current flowing through resistor 28 and rectifier 4 is blocked. The rectified output is derived from a low resistance 6 and is applied to the grid of an oscillator valve 7 in series with the frequency determining circuit 15, 16 to control the oscillation output. In order to ensure that when the pilot level is low the oscillation amplitude does not rise sufficiently to burn out the thermistor, part of the output is applied to a rectifier circuit 20, 21. This circuit is biased by a potentiometer 24 so that as the pilot decreases below a certain level and the oscillator output correspondingly increases, an increasing negative voltage appears across resistor 22. At the same time the voltage across resistor 6 is decreasing and when the former voltage exceeds the latter, rectifier 23 conducts and applies a bias to the grid to limit the oscillation amplitude. The anode load of the amplifier valve 3 may be replaced by a tuned circuit or a transmission line resonant at the fundamental and a harmonic of the pilot frequency.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB296197X | 1950-02-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB681023A true GB681023A (en) | 1952-10-15 |
Family
ID=10294435
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB4969/50A Expired GB681023A (en) | 1950-02-27 | 1950-02-27 | Improvements in or relating to automatic level control devices for electric carrier current communication systems |
Country Status (4)
| Country | Link |
|---|---|
| BE (1) | BE501513A (en) |
| CH (1) | CH296197A (en) |
| FR (1) | FR1044600A (en) |
| GB (1) | GB681023A (en) |
-
0
- BE BE501513D patent/BE501513A/xx unknown
-
1950
- 1950-02-27 GB GB4969/50A patent/GB681023A/en not_active Expired
-
1951
- 1951-02-26 FR FR1044600D patent/FR1044600A/en not_active Expired
- 1951-02-27 CH CH296197D patent/CH296197A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| BE501513A (en) | |
| CH296197A (en) | 1954-01-31 |
| FR1044600A (en) | 1953-11-19 |
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