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1. (WO1987003755) CASCADED INTERNAL IMPEDANCE DEPENDENT AMPLIFIER WITH ACCURATE VARIABLE GAIN CONTROL
Latest bibliographic data on file with the International Bureau

Pub. No.: WO/1987/003755 International Application No.: PCT/US1986/001979
Publication Date: 18.06.1987 International Filing Date: 22.09.1986
IPC:
G01S 13/44 (2006.01) ,G01S 7/40 (2006.01) ,H03G 3/00 (2006.01) ,H03G 3/30 (2006.01)
G PHYSICS
01
MEASURING; TESTING
S
RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
13
Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
02
Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
06
Systems determining position data of a target
42
Simultaneous measurement of distance and other coordinates
44
Monopulse radar, i.e. simultaneous lobing
G PHYSICS
01
MEASURING; TESTING
S
RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
7
Details of systems according to groups G01S13/, G01S15/, G01S17/127
02
of systems according to group G01S13/58
40
Means for monitoring or calibrating
H ELECTRICITY
03
BASIC ELECTRONIC CIRCUITRY
G
CONTROL OF AMPLIFICATION
3
Gain control in amplifiers or frequency changers
H ELECTRICITY
03
BASIC ELECTRONIC CIRCUITRY
G
CONTROL OF AMPLIFICATION
3
Gain control in amplifiers or frequency changers
20
Automatic control
30
in amplifiers having semiconductor devices
Applicants:
HUGHES AIRCRAFT COMPANY [US/US]; 7200 Hughes Terrace Los Angeles, CA 90045-0066, US
Inventors:
YANG, Steve, S.; US
Agent:
BROWN, Charles, D. @; Hughes Aircraft Company Post Office Box 45066, Bldg. C1, M/S A-126 Los Angeles, CA 90045-0066, US
Priority Data:
809,62816.12.1985US
Title (EN) CASCADED INTERNAL IMPEDANCE DEPENDENT AMPLIFIER WITH ACCURATE VARIABLE GAIN CONTROL
(FR) AMPLIFICATEUR EN CASCADE DEPENDANT DE L'IMPEDANCE INTERNE ET POURVU D'UNE COMMANDE DE GAIN VARIABLE DE PRECISION
Abstract:
(EN) An internal impedance dependent amplifier has a gain as determined by the impedance at a predetermined node within the amplifier. A PIN diode (42) is coupled to the predetermined node (26). The PIN diode (21) is driven with a forward biased current (Ip) which serves as the accurate gain control signal for the amplifier. In the preferred embodiment, the PIN diode (42) is driven by an operational amplifier (56) in such a manner that the impedance thus coupled to the predetermined node in the amplifier is temperature independent. Because the PIN diode has an impedance given by: log R = A + B log Ip, where R is the impedance of the PIN diode; Ip is the forward biasing current; and A and B constants which are different for each PIN diode, the voltage (Vc) applied to the operational amplifier (56) driving the PIN diode (42) is linear with respect to the impedance of the PIN diode (42) and hence the voltage gain of the impedance controlled amplifier to which the PIN diode is coupled. This characteristic of the gain of the amplifier allows the amplifier to be cascaded in series (A1 ... A11) and to preserve the same impedance relation as expressed above for the cascaded series of amplifiers as well. Thus, the gain in dB of the cascaded series of amplifiers is log linear with respect to a common control voltage applied to each of the amplifiers of the series.
(FR) Le gain d'un amplificateur dépendant de l'impédance interne est déterminé par l'impédance en un point nodal prédéterminé dans l'amplificateur. Une diode PIN (42) est couplée au point nodal prédéterminé (26). La diode PIN (21) est attaquée avec un courant (UP) polarisé en sens direct servant de signal de commande de gain de précision pour l'amplificateur. Dans le mode préféré de réalisation, la diode PIN (42) est attaquée par un amplificateur opérationnel (56) de telle sorte que l'impédance ainsi couplée au point nodal prédéterminé dans l'amplificateur soit indépendante de la température. Etant donné que l'impédance de la diode PIN est donnée par la formule log R = A + B log Ip (où R est l'impédance de la diode PIN; Ip est le courant de polarisation en sens direct; et A et B sont des constantes différentes pour chaque diode PIN), la tension (Vc) appliquée à l'amplificateur opérationnel (56) attaquant la diode PIN (42) est linéaire par rapport à l'impédance de la diode PIN (42), de même que pour le gain de tension de l'amplificateur commandé par l'impédance auquel la diode PIN est couplée. Cette caractéristique du gain de l'amplificateur lui permet d'être monté en série en cascade (A1 ... A11), tout en conservant la même relation d'impédance exprimée ci-dessus pour la série en cascade d'amplificateurs. Le gain en dB de la série d'amplificateurs en cascade est par conséquent logarithmique linéaire par rapport à une tension de commande commune appliquée à chacun des amplificateurs de la série.
Designated States: AU, DK, JP, KR, NO
European Patent Office (BE, CH, DE, FR, GB, IT, NL, SE)
Publication Language: English (EN)
Filing Language: English (EN)
Also published as:
NO19873082ES2002790EP0250453KR1019880701044AU1986064040