GB1393245A - Transmitter arrangements - Google Patents

Transmitter arrangements

Info

Publication number
GB1393245A
GB1393245A GB1364971A GB1364971A GB1393245A GB 1393245 A GB1393245 A GB 1393245A GB 1364971 A GB1364971 A GB 1364971A GB 1364971 A GB1364971 A GB 1364971A GB 1393245 A GB1393245 A GB 1393245A
Authority
GB
United Kingdom
Prior art keywords
amplifier
comparator
gain
antenna
fast
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
Application number
GB1364971A
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.)
Plessey Co Ltd
Original Assignee
Plessey Co Ltd
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 Plessey Co Ltd filed Critical Plessey Co Ltd
Priority to GB1364971A priority Critical patent/GB1393245A/en
Publication of GB1393245A publication Critical patent/GB1393245A/en
Expired legal-status Critical Current

Links

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
    • H03G3/3036—Automatic control in amplifiers having semiconductor devices in high-frequency amplifiers or in frequency-changers
    • H03G3/3042—Automatic control in amplifiers having semiconductor devices in high-frequency amplifiers or in frequency-changers in modulators, frequency-changers, transmitters or power amplifiers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/52—Circuit arrangements for protecting such amplifiers

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Transmitters (AREA)

Abstract

1393245 Radio transmitting systems PLESSEY CO Ltd 21 July 1972 [7 May 1971] 13649/71 Heading H4L A transistorized transmitter amplifier 4 is protected from overload by a feedback circuit having fast and slow response channels 12, 13. A low-pass filter 5 connects the amplifier 4 to an antenna and tuning unit, and reflectometers 7, 8 detect the presence of reflected power due to mismatch of filter or antenna respectively. Such reflection presents the amplifier with a high V.S.W.R. load, and to prevent damage, a selector 11 acts in response to the larger of the two reflectometer outputs and feeds it to the fast response comparator 12 and the slow response comparator 13 wherein it is compared with preset levels 1, 2. The comparators control the gain of an r.y. amplifier driving the transmitter amplifier 4. In the event of an a.m. signal being applied to the r.f. amplifier and an excessive output voltage (16, Fig. 3, not shown), occurring due to mismatch of the filter or the antenna, the fast action comparator rapidly reduces the gain of r.f. amplifier 1. Due to the low time constant of comparator 1 however, it quickly follows the resulting drop in output to increase the gain, and flattening of the output signal occurs due to successive changes in the gain control signal (F7, Fig. 4, not shown). The slow response comparator, however, takes over in about 10 ms. (dotted line, Fig. 4), and linear amplification of the signal proceeds.
GB1364971A 1971-05-07 1971-05-07 Transmitter arrangements Expired GB1393245A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1364971A GB1393245A (en) 1971-05-07 1971-05-07 Transmitter arrangements

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1364971A GB1393245A (en) 1971-05-07 1971-05-07 Transmitter arrangements

Publications (1)

Publication Number Publication Date
GB1393245A true GB1393245A (en) 1975-05-07

Family

ID=10026879

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1364971A Expired GB1393245A (en) 1971-05-07 1971-05-07 Transmitter arrangements

Country Status (1)

Country Link
GB (1) GB1393245A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0748040A1 (en) * 1995-06-06 1996-12-11 Eni, A Division Of Astec America, Inc. Gain stability arrangement for HV MOSFET power amplifier

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0748040A1 (en) * 1995-06-06 1996-12-11 Eni, A Division Of Astec America, Inc. Gain stability arrangement for HV MOSFET power amplifier

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Legal Events

Date Code Title Description
PS Patent sealed
PLNP Patent lapsed through nonpayment of renewal fees