Patent US1861516A successfully refreshed from Google Patents.
EP0397401A2
Expired / Lapsed
EP
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Circuit for forming low power levels in a transmitter of a radio telephone
Assignee: Nokia Oyj
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Filing: 1990-05-03
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Granted: —
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Expires: 2010-05-03
Abstract
Abstract The present invention concerns a circuit for forming low power levels in a transmitter of a radio telephone. By a power amplifier (1) of the transmitter is formed the maximum power level and a plurality of lower power levels. As taught by the invention, very low power levels can be produced by controling the power of the RF signal leaking through the power amplifier (1) when said signal is not amplified by the power amplifier. For controlling the leakage power, a PIN diode attenuator (4) connected before the power amplifier (1) is used.
Inventors
- 👤 Risto Väisänen
- 👤 Jukka Sarasmo
- 👤 Vesa Pekkarinen
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 16:24
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3036; H03G3/3042; H04; H04B; H04B1/00; H04B1/02; H04B1/04; H04B2001/0408; H04B2001/0416
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
104 words
A circuit for forming low power levels in a transmitter of a radio telephone transmitter, comprising a controllable, C class power amplifier of one or several stages, wherewith the maximum power level and a plurality of lower power levels are produced, characterized in that in series with the power amplifier (1) is coupled a controllable attenuator (4), which does not attenuate a radio frequency signal (RF signal) when said signal is being amplified in the power amplifier (1), but with which a RF signal may be attenuated or not be attenuated when said signal is not being amplified (TXC1=0) in the power amplifier (1).
Claim 2
Dependent Claim
104 words
A circuit for forming low power levels in a transmitter of a radio telephone transmitter, comprising a controllable, C class power amplifier of one or several stages, wherewith the maximum power level and a plurality of lower power levels are produced, characterized in that in series with the power amplifier (1) is coupled a controllable attenuator (4), which does not attenuate a radio frequency signal (RF signal) when said signal is being amplified in the power amplifier (1), but with which a RF signal may be attenuated or not be attenuated when said signal is not being amplified (TXC1=0) in the power amplifier (1).
Claim 3
Dependent Claim
19 words
A circuit according to claim 1, characterized in that the attenuator (4) is connected before the power amplifier (1).
Claim 4
Dependent Claim
34 words
A circuit according to claim 1, characterized in that the attenuator (4) is a PIN diode attenuator, which is controlled by a control voltage (TXC2) derived from the control logic of the radio telephone.
Claim 5
Dependent Claim
36 words
A circuit according to claim 1, characterized in that the attenuator (4) is a voltage or current controlled amplifier which is controlled by the control voltage (TXC2) derived from the control logic of the radio telephone.
Claim 6
Dependent Claim
85 words
A circuit according to claim 1, characterized in that the gain of the power amplifier (1) is controlled by a reference amplifier (3), to a first input whereof entering the control voltage (TXC1) derived from the control logic of the radio telephone, and to a second input, a voltage proportional to the power of the output of the power amplifier (1), derived from the power pick-up (2), whereby the power amplifier (1), the reference amplifier (3) and the power pick-up (2) constitute a control loop.
Claim 7
Dependent Claim
29 words
A circuit according to any one of the preceding claims, characterized in that it is used in a transmitter of a digital radio telephone, e.g. in the gsm system.
References Cited (Backward Citations)
No citation records indexed.
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