EP0431201A1
Expired / Lapsed
EP
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Linear transmitter
Assignee: NTT Docomo Inc
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Filing: 1990-06-28
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Granted: —
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Expires: 2010-06-28
Abstract
Abstract A linear transmitter which controls a bias voltage of the drain electrode or the collector electrode of a high-frequency amplifier based on an envelope of modulated waves, wherein the envelope is formed by using in-phase envelope components and orthogonal envelope components obtained from the base band signals; and the bias voltage of the high-frequency amplifier is controlled by the processing of digital operation.
Inventors
- 👤 Kouji Chiba
- 👤 Toshio Nojima
- 👤 Yasushi Yamao
- 👤 Shigeru 4622-3 Kamariyacho Tomisato
- 👤 Tadao Takami
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 03:41
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/02; H03F1/0205; H03F1/0211; H03F1/0216; H03F1/0222; H03F1/0227; H03C; H03C1/00; H03F1/32; H03F1/3223; H03F3/00; H03F3/20; H03F3/24; H04; H04B; H04B1/00; H04B1/02; H04B1/04; H04B2001/0408; H04B2001/0441
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
145 words
A linear transmitter including a modulation unit which modulates an input signal in amplitude, a RF power amplifier which amplifies the modulated signal outputted from said modulator with solid state amplification device with grounded source or grounded emitter, and a bias means which outputs a DC voltage substantially proportionate to the envelope of said modulated signal as the bias voltage of said power amplifier, which is characterized in that said modulation unit includes a complex envelope generator which generates in-phase envelope component and quadrature envelope component of the modulated signal out of the input signal and a quadrature modulator which generates the modulated signal with said in-phase envelope component and quadrature envelope component, and that there is provided an envelope generating means which obtains the envelope out of said in-phase envelope component and said quadrature envelope component and supplies the same to said bias means.
Claim 2
Dependent Claim
36 words
The linear transmitter as claimed in Claim 1 wherein the envelope generating means includes a numerical arithmetic processor which obtains the envelope by digital operation out of the input in-phase envelope component and quadrature envelope component.
Claim 3
Dependent Claim
37 words
The linear transmitter as claimed in Claim 1 wherein the envelope generating means includes a memory table which outputs values that have been written-in in advance corresponding to the input in-phase envelope component and quadrature envelope component.
Claim 4
Dependent Claim
41 words
The linear transmitter as claimed in Claim 1 wherein a delay time adjusting means is provided which makes the waveform of the modulated signal inputted at the power amplifier for radio frequency agree timewise with the waveform of the bias voltage.
Claim 5
Dependent Claim
35 words
The linear transmitter as claimed in Claim 1 wherein a frequency equalizer is provided which equalizes the output amplitude and the phase of the envelope generating means and supplies the same to the bias means.
Claim 6
Dependent Claim
50 words
The linear transmitter as claimed in Claim 1 wherein a minimum bias voltage holding means is included which maintains the voltage outputted from the bias means at a given value or higher when the signal level of the envelope outputted from the envelope generating is lower than a prescribed value.
Claim 7
Dependent Claim
74 words
The linear transmitter as claimed in Claim 6 wherein the minimum bias voltage holding means includes a signal converter which supplies a signal of substantially constant value to the bias means when the signal level of the envelope outputted from the envelope generating means is lower than a prescribed value, and supplies a signal substantially proportionate to said signal level to the bias means when said signal level is greater than said prescribed value.
Claim 8
Dependent Claim
67 words
The linear transmitter as claimed in Claim 1 which further includes an output detector which obtains the envelope of the modulated signal outputted from the power amplifier for radio frequency, and an envelope compensating means which compensates the signal level of the envelope supplied to the bias means with the difference between the output from the output detecting means and the output from the envelope generating means.
Claim 9
Dependent Claim
65 words
The linear transmitter as claimed in Claim 1 which includes an output detecting means which obtains the envelope of the modulated signal outputted from the RF power amplifier, and an input control means which controls the amplitude of the modulated signal inputted at said power amplifier with the difference between the output from the output detecting means and the output from the envelope generating means.
Claim 10
Dependent Claim
80 words
The linear transmitter as claimed in Claim 1 which includes solid state amplification device in cascade. connection, and which comprises an output detecting means which obtains the envelope of the modulated signal outputted from the final stage of the cascade-connected semiconductor device, and a means which controls the bias voltage at the first or middle stage of said cascade-connected semiconductor device with the difference between the output from the output detecting means and the output from the envelope generating means.
Claim 11
Dependent Claim
35 words
The linear transmitter as claimed in any of the claims 8 through 10 which includes a detector characteristic compensating means which compensates the characteristic difference between the envelope generating means and the output detecting means.
Claim 12
Dependent Claim
43 words
The linear transmitter as claimed in Claim 11 wherein the detector characteristic compensating means includes a means which compensates the output from the envelope generating means by means of a circuit having non-linearity substantially identical to the characteristics of the output detecting means.
References Cited (Backward Citations)
No citation records indexed.
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