CA1164054A - Radio transmitter having an output power control circuit - Google Patents
Radio transmitter having an output power control circuitInfo
- Publication number
- CA1164054A CA1164054A CA000368156A CA368156A CA1164054A CA 1164054 A CA1164054 A CA 1164054A CA 000368156 A CA000368156 A CA 000368156A CA 368156 A CA368156 A CA 368156A CA 1164054 A CA1164054 A CA 1164054A
- Authority
- CA
- Canada
- Prior art keywords
- power
- directional coupler
- output
- detector
- radio transmitter
- 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
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/04—TPC
- H04W52/52—TPC using AGC [Automatic Gain Control] circuits or amplifiers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers without distortion of the input signal
- 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
Abstract
ABSTRACT
A radio transmitter for use in a mobile communication system is disclosed. To maintain the radio signal intensity at the base station within prescribed limits it is necessary to control the transmitter power output to compensate for varying distances between the mobile unit and the base station.
Typically, the conventional control circuit comprises a power amplifier, a directional coupler coupled to the power amplifier, a detector detecting the forward power of the coupler, a generator generating a difference voltage between the output voltage of the detector and a reference voltage and a power regulator to regulate the output power of the power amplifier in response to the difference voltage. The transmitter power is changed by varying the reference voltage in response to control signals. A disadvantage of the conventional system is that it has a narrow range in which the output power is controllable. According to the invention disclosed, additional circuitry is provided for varying electrically the coupling coefficient of the directional coupler, thereby extending the con-trollable range of the transmitter output power.
A radio transmitter for use in a mobile communication system is disclosed. To maintain the radio signal intensity at the base station within prescribed limits it is necessary to control the transmitter power output to compensate for varying distances between the mobile unit and the base station.
Typically, the conventional control circuit comprises a power amplifier, a directional coupler coupled to the power amplifier, a detector detecting the forward power of the coupler, a generator generating a difference voltage between the output voltage of the detector and a reference voltage and a power regulator to regulate the output power of the power amplifier in response to the difference voltage. The transmitter power is changed by varying the reference voltage in response to control signals. A disadvantage of the conventional system is that it has a narrow range in which the output power is controllable. According to the invention disclosed, additional circuitry is provided for varying electrically the coupling coefficient of the directional coupler, thereby extending the con-trollable range of the transmitter output power.
Description
~ 1 64()~4 RADIO TR~NS~IITTER HA~f'ING AN
OUTPUT POWER CONTROL CIRCUIT
The present invention concerns a radio transmitter, and more particularly, a circuit for controlling the output power for the radio tran smitte r .
In a radio communication system such as a mobile communication 5 system where the communication distance between a base station and a mobile unit greatly varies from moment to moment, it is necessary to control the transmitter output power so that the radio signal intensity at the base station lies within a prescribed level.
A conventional transmitter output power control circuit (for 10 example, T 196 miniphone marketed by TAIT ELECTRONICS LTD. ) comprises a power amplifier, a coupler coupled to the output of said power amplifier, a detector to detect the forward power of the directional coupler, means to provide a difference voltage between the DC output voltage of the detector and a reference voltage, and 15 a power regulator means to regulate the output power of the power amplifier in response to the difference voltage.
In such a control circuit, the transmitter output power is changed by varying the reference voltage In response to control signals.
This reference voltage may be varied extensively, but the minimum po~er 20 pD~: detectable by the detector diode to be used in the detector is about several mW (milli watt), while the allowable maximum input 7~
~ 1 64054 power is about several hundred mW. Accordingly, where the coupling coefficient of the directional coupler is fi~ed, the range of variation for the detectable output power is about 20 dB or less. Thus, the conventional control circuit has a narrow range in which the transmitter output power range is controllable.
An object of the present invention is therefore to provide a trans-mitter power control circuit for a transmitter which has wide controllable range for the transmitter output power.
According to the present invention, there is provided a radio trans-mitter having a forward power output control circuit comprising power amplifier means, directional coupler means coupled to said power amplifier means, detector means for detecting the forward power output of said direc-tional coupler means, generator means for generating a difference voltage responsive to the difference between an output voltage of said detector means and a reference voltage, power regulator means for varying the output power for said power amplifier means in response to the output of said generator means, means for providing a control signal depending on whether or not an electric field intensity of a receiving signal exceeds a predetermined value, and first means between said directional coupler means and said detector means for varying the power applied from said power amplifier means via said directional coupler to said detector means in response to said control signal, thereby extending the controllable range for output power of said radio transmitter.
In a preferred embodiment of the invention, said directional coupler means has a coupling point and said first means comprises a capacitor and means responsive to said control signal for coupling therethrough said capa-citor between said coupling point and a potential point.
~ - .
~ -2-~ 3 6~05 ~
According to another preferred embodiment of the invention, said directional coupler means has a coupling point and said first means comprises a second means coupled between said directional coupler means and said detec-tor means for attenuating the power applied from said directional coupler means to said detector means.
The present invention will now be described in greater detail with reference to the accompanying drawings wherein:
Figure 1 is a block diagram showing an example of a conventional transmitter power control circuit;
Figure 2 shows the input/output characteristics of a differential amplifier to explain the operation of Figure l;
Figure 3 is a block diagram showing an embodiment of output power control circuit for transmitter in accordance with the present invention; and Figure 4 is a block diagram showing another embodiment of transmitter output power control circuit in accordance with the present invention.
Now referring to Figure 1, description is given for operation where a switch 8 is opened. At modulator 1, a carrier wave is modulated by the signals supplied to a terminal 10, which is then supplied to a power amplifier 3 via a PIN diode variable attenuator 2 ~or a power regulator). The output 2a (or forward power) of the power amplifier 3 is applied to antenna 11 via a directional coupler 4 and a transmit/receive section 13, a portion of which is detected by a detector 5 ~comprising a detector diode 51, a resistor 52 and a capacitor 53). The detector 5 provides a voltage Vin which is 1 ~ 64()5~
applied to the inverting input terminal of an inverting amplifier 6 (comprising a differential amplifier 61 and resistors 62, 63).
The output voltage VOut of the amplifier 6 changes in response to Vin as shown by the solid line in Fig. 2. In Figs. 1 and 2, Es is a voltage to be applied to the non-inverting input terminal of the amplifier 6 and is given by a reference voltage generator 7 (comprising a DC power source 71 and a resistor 72). V,,Ut is applied to the PIN diode variable attenuator 2, and changes the input power to the power amplifier ~ and, consequently its output power as well. The control loop extending from the power amplifier 3 to the PIN diode variable attenuator 2 via the directional coupler 4, the detector 5 and the amplifier 6 forms a negative feedback loop.
Es is adjusted so as to obtain Vout corresponding to a predetermined Vin, or a predetermined trans~nitter output power. These voltages are denoted as Vll, ESl and Vol, respectively. By the above-mentioned negative feedback operation, the output power level is maintained at a level corresponding to Esl.
When the switch 8 is next closed in response to the high level control signal applied to the terminal 9, the po~,ver source voltage is divided by the resistances 72 and 12, Esl becomes Es2 (Es2 < Esl), and the transmitter output power level is lowered depending in Es2.
The operating point of the operational amplifier is the points (V12, V02) shown in Fig. 2.
~ 3 6~0~l1 In the mobile communication system, the control signal is automatically supplied to the terminal 9 from an electric field intensity detector 15 (comprising an amplifier, a rectifier and a level comparator, for example) via a switch 17 and an OR gate 18.
5 The detector 15 detects whether or not the electric field intensity of a modulated carrier wave from the base station exceeds a predetermined value, or whether or not the mobile unit approaches the base station within a predetermined range, to provide high or low level control signal.
Also, the control signal is manually supplied to the terminal 9 from a manual switch 16 via the OR gate 18. In the manual operation, the switch 17 is opened. On the other hand, in the automatic operation, the switches 16 and 17 are respectively set in the states such as shown in Fig. 1. Reference numeral 14 denotes a receiver section 15 which receives and demodulates the modulated carrier wave transmitted from the base station via the antenna 11 and the transmission/reception section 13.
In the conventional transmitter output power control circuit mentioned above, the coupling coefficient of the directional coupler 20 is fixed. Also, the detector diode 51 has the upper and the lower lilnits for detection of the power. Accordingly, if the coupling coefficient of the directional coupler is set at a large value, the lower limit of the controllable transmitter output power becomes higher, but Lt is not possible to lower the upper limit of the transmitter output power.
~ 1 ~405~
On the other hand, if the coupling coefficient of the directional coupler is set at a small value, the upper limit becomes higher, but it is impossible to lower the lower limit.
In Fig. 3 showing the transmitter output power control circuit according to the present invention, the same reference numerals as those shown in Fig. 1 denote the same functions~ The feature of the control circuit shown in Fig. 3 lies in that a capacitor 21 is coupled to a coupling port 30 of the directional coupler 4 via a switch 20. The switch 20 is connected to a control signal terminal 9 via an inverter circuit 22. Accordingly, when the switch 8 is open, the switch 20 is closed. Thus, the two switches are opened and closed in a complementary relationship to each other. The coupling coefficent of the directional coupler 4 is set at a value larger than that of Fig. 1. For instance, it is set at a value larger by 10 dB
lS to facilitate explanation. When the switch 8 is open and the switch 20 is closed, the capacitor 21 is grounded.
The total coupling coefficient ~3 T then is given by, the following formula;
~ T = ~ o/l + (2 CZof)2 wherein ~ O denotes coupling coefficient of the directional coupler 4;
C, capacitance of the capacitor 21;
Zo, characteristic impedance of the coupling port transmission line of the directional coupler 4; and f, transmission signal frequency.
When f = ~00 MHz, ZO = 50 S~, and C - 21 pF, .
..
i 1 ~40~4 the total coupling coefficient tgT is aboutl~30hO,and, accordin,,l~
equals to the coupling coefficient of the coupler 4 in Fia. 1.
In other words, the upper limit of the controllable power level becomes the same as in Fia. 1. On the other hand, when the 5 switch 8 is closed and the switch 20 is open, ~ T = ~ o The coupling coefficient is larger than that of Fig. 1 by 10 dB, and accordingly. the lower limit of the controllable output level can be lowered by 10 dB compared to that in Fig. 1. In other ~,vords, variation in the coupling coefficient of the directional coupler 4 10 by using the capacitor 21 results in extensive variation in the transmitter output power. In the preceding description, one switch 20 controls one capacitor 22 in response to a control signal to change the coupling coefficient of the coupler 4, but a plurality of switches may control a plurality of capacitors in response to a 15 plurality of control signals.
In Fig. 4 showing another embodiment of the transmitter power control circuit according to the present invention, the same reference numerals as those shown in Figs. 1 and 3 denote the same functions. The feature of the control circuit shown in Fig. 4 lies 20 in that a PIN diode attenuator is provided between the directional coupler 4 with a fixed coupling coefficient and the detector 5. When the switch 8 is opened in response to the control signal applied to the terminal 9, PIN diodes 212 and 222 become ON and OFF, respectively.
When the switch 8 is closed, the PIN diodes 212 and 222 become i 1 64n5~
OFF and ON, respectively. The coupling coefficient of the directional coupler ~ is set at a value larger by 10 dB than that shown in Fig. 1, and the variable resistor 215 is adjusted to set the attenuation by the PIN diode 212 at 10 dB in advance. Similarly, 5 the attenuation at the PIN diode Z22 is set at the smallest possible value (usually about 2 dB) by adjusting the variable resistor 225.
It will be clear, then, that the controllable limits of the output power can be extensively changed similarly as described in respect of the embodiment shown in Fig. 3.
The reference numerals 211, 221, 213 and 223 denote DC
blocking capacitors; 217 and 227, RF by-passing capacitors; and 214, 224, 216 and 226, RF blocking choke coils.
As described heretofore, the transmitter power control circuit in accordance with the present invention enables extension 15 of the range of controllable output power level.
OUTPUT POWER CONTROL CIRCUIT
The present invention concerns a radio transmitter, and more particularly, a circuit for controlling the output power for the radio tran smitte r .
In a radio communication system such as a mobile communication 5 system where the communication distance between a base station and a mobile unit greatly varies from moment to moment, it is necessary to control the transmitter output power so that the radio signal intensity at the base station lies within a prescribed level.
A conventional transmitter output power control circuit (for 10 example, T 196 miniphone marketed by TAIT ELECTRONICS LTD. ) comprises a power amplifier, a coupler coupled to the output of said power amplifier, a detector to detect the forward power of the directional coupler, means to provide a difference voltage between the DC output voltage of the detector and a reference voltage, and 15 a power regulator means to regulate the output power of the power amplifier in response to the difference voltage.
In such a control circuit, the transmitter output power is changed by varying the reference voltage In response to control signals.
This reference voltage may be varied extensively, but the minimum po~er 20 pD~: detectable by the detector diode to be used in the detector is about several mW (milli watt), while the allowable maximum input 7~
~ 1 64054 power is about several hundred mW. Accordingly, where the coupling coefficient of the directional coupler is fi~ed, the range of variation for the detectable output power is about 20 dB or less. Thus, the conventional control circuit has a narrow range in which the transmitter output power range is controllable.
An object of the present invention is therefore to provide a trans-mitter power control circuit for a transmitter which has wide controllable range for the transmitter output power.
According to the present invention, there is provided a radio trans-mitter having a forward power output control circuit comprising power amplifier means, directional coupler means coupled to said power amplifier means, detector means for detecting the forward power output of said direc-tional coupler means, generator means for generating a difference voltage responsive to the difference between an output voltage of said detector means and a reference voltage, power regulator means for varying the output power for said power amplifier means in response to the output of said generator means, means for providing a control signal depending on whether or not an electric field intensity of a receiving signal exceeds a predetermined value, and first means between said directional coupler means and said detector means for varying the power applied from said power amplifier means via said directional coupler to said detector means in response to said control signal, thereby extending the controllable range for output power of said radio transmitter.
In a preferred embodiment of the invention, said directional coupler means has a coupling point and said first means comprises a capacitor and means responsive to said control signal for coupling therethrough said capa-citor between said coupling point and a potential point.
~ - .
~ -2-~ 3 6~05 ~
According to another preferred embodiment of the invention, said directional coupler means has a coupling point and said first means comprises a second means coupled between said directional coupler means and said detec-tor means for attenuating the power applied from said directional coupler means to said detector means.
The present invention will now be described in greater detail with reference to the accompanying drawings wherein:
Figure 1 is a block diagram showing an example of a conventional transmitter power control circuit;
Figure 2 shows the input/output characteristics of a differential amplifier to explain the operation of Figure l;
Figure 3 is a block diagram showing an embodiment of output power control circuit for transmitter in accordance with the present invention; and Figure 4 is a block diagram showing another embodiment of transmitter output power control circuit in accordance with the present invention.
Now referring to Figure 1, description is given for operation where a switch 8 is opened. At modulator 1, a carrier wave is modulated by the signals supplied to a terminal 10, which is then supplied to a power amplifier 3 via a PIN diode variable attenuator 2 ~or a power regulator). The output 2a (or forward power) of the power amplifier 3 is applied to antenna 11 via a directional coupler 4 and a transmit/receive section 13, a portion of which is detected by a detector 5 ~comprising a detector diode 51, a resistor 52 and a capacitor 53). The detector 5 provides a voltage Vin which is 1 ~ 64()5~
applied to the inverting input terminal of an inverting amplifier 6 (comprising a differential amplifier 61 and resistors 62, 63).
The output voltage VOut of the amplifier 6 changes in response to Vin as shown by the solid line in Fig. 2. In Figs. 1 and 2, Es is a voltage to be applied to the non-inverting input terminal of the amplifier 6 and is given by a reference voltage generator 7 (comprising a DC power source 71 and a resistor 72). V,,Ut is applied to the PIN diode variable attenuator 2, and changes the input power to the power amplifier ~ and, consequently its output power as well. The control loop extending from the power amplifier 3 to the PIN diode variable attenuator 2 via the directional coupler 4, the detector 5 and the amplifier 6 forms a negative feedback loop.
Es is adjusted so as to obtain Vout corresponding to a predetermined Vin, or a predetermined trans~nitter output power. These voltages are denoted as Vll, ESl and Vol, respectively. By the above-mentioned negative feedback operation, the output power level is maintained at a level corresponding to Esl.
When the switch 8 is next closed in response to the high level control signal applied to the terminal 9, the po~,ver source voltage is divided by the resistances 72 and 12, Esl becomes Es2 (Es2 < Esl), and the transmitter output power level is lowered depending in Es2.
The operating point of the operational amplifier is the points (V12, V02) shown in Fig. 2.
~ 3 6~0~l1 In the mobile communication system, the control signal is automatically supplied to the terminal 9 from an electric field intensity detector 15 (comprising an amplifier, a rectifier and a level comparator, for example) via a switch 17 and an OR gate 18.
5 The detector 15 detects whether or not the electric field intensity of a modulated carrier wave from the base station exceeds a predetermined value, or whether or not the mobile unit approaches the base station within a predetermined range, to provide high or low level control signal.
Also, the control signal is manually supplied to the terminal 9 from a manual switch 16 via the OR gate 18. In the manual operation, the switch 17 is opened. On the other hand, in the automatic operation, the switches 16 and 17 are respectively set in the states such as shown in Fig. 1. Reference numeral 14 denotes a receiver section 15 which receives and demodulates the modulated carrier wave transmitted from the base station via the antenna 11 and the transmission/reception section 13.
In the conventional transmitter output power control circuit mentioned above, the coupling coefficient of the directional coupler 20 is fixed. Also, the detector diode 51 has the upper and the lower lilnits for detection of the power. Accordingly, if the coupling coefficient of the directional coupler is set at a large value, the lower limit of the controllable transmitter output power becomes higher, but Lt is not possible to lower the upper limit of the transmitter output power.
~ 1 ~405~
On the other hand, if the coupling coefficient of the directional coupler is set at a small value, the upper limit becomes higher, but it is impossible to lower the lower limit.
In Fig. 3 showing the transmitter output power control circuit according to the present invention, the same reference numerals as those shown in Fig. 1 denote the same functions~ The feature of the control circuit shown in Fig. 3 lies in that a capacitor 21 is coupled to a coupling port 30 of the directional coupler 4 via a switch 20. The switch 20 is connected to a control signal terminal 9 via an inverter circuit 22. Accordingly, when the switch 8 is open, the switch 20 is closed. Thus, the two switches are opened and closed in a complementary relationship to each other. The coupling coefficent of the directional coupler 4 is set at a value larger than that of Fig. 1. For instance, it is set at a value larger by 10 dB
lS to facilitate explanation. When the switch 8 is open and the switch 20 is closed, the capacitor 21 is grounded.
The total coupling coefficient ~3 T then is given by, the following formula;
~ T = ~ o/l + (2 CZof)2 wherein ~ O denotes coupling coefficient of the directional coupler 4;
C, capacitance of the capacitor 21;
Zo, characteristic impedance of the coupling port transmission line of the directional coupler 4; and f, transmission signal frequency.
When f = ~00 MHz, ZO = 50 S~, and C - 21 pF, .
..
i 1 ~40~4 the total coupling coefficient tgT is aboutl~30hO,and, accordin,,l~
equals to the coupling coefficient of the coupler 4 in Fia. 1.
In other words, the upper limit of the controllable power level becomes the same as in Fia. 1. On the other hand, when the 5 switch 8 is closed and the switch 20 is open, ~ T = ~ o The coupling coefficient is larger than that of Fig. 1 by 10 dB, and accordingly. the lower limit of the controllable output level can be lowered by 10 dB compared to that in Fig. 1. In other ~,vords, variation in the coupling coefficient of the directional coupler 4 10 by using the capacitor 21 results in extensive variation in the transmitter output power. In the preceding description, one switch 20 controls one capacitor 22 in response to a control signal to change the coupling coefficient of the coupler 4, but a plurality of switches may control a plurality of capacitors in response to a 15 plurality of control signals.
In Fig. 4 showing another embodiment of the transmitter power control circuit according to the present invention, the same reference numerals as those shown in Figs. 1 and 3 denote the same functions. The feature of the control circuit shown in Fig. 4 lies 20 in that a PIN diode attenuator is provided between the directional coupler 4 with a fixed coupling coefficient and the detector 5. When the switch 8 is opened in response to the control signal applied to the terminal 9, PIN diodes 212 and 222 become ON and OFF, respectively.
When the switch 8 is closed, the PIN diodes 212 and 222 become i 1 64n5~
OFF and ON, respectively. The coupling coefficient of the directional coupler ~ is set at a value larger by 10 dB than that shown in Fig. 1, and the variable resistor 215 is adjusted to set the attenuation by the PIN diode 212 at 10 dB in advance. Similarly, 5 the attenuation at the PIN diode Z22 is set at the smallest possible value (usually about 2 dB) by adjusting the variable resistor 225.
It will be clear, then, that the controllable limits of the output power can be extensively changed similarly as described in respect of the embodiment shown in Fig. 3.
The reference numerals 211, 221, 213 and 223 denote DC
blocking capacitors; 217 and 227, RF by-passing capacitors; and 214, 224, 216 and 226, RF blocking choke coils.
As described heretofore, the transmitter power control circuit in accordance with the present invention enables extension 15 of the range of controllable output power level.
Claims (4)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A radio transmitter having a forward power output control circuit prising power amplifier means, directional coupler means coupled to said power amplifier means, detector means for detecting the forward power output of said directional coupler means, generator means for generating a difference voltage responsive to the difference between an output voltage of said detec-tor means and a reference voltage, power regulator means for varying the output power for said power amplifier means in response to the output of said gener-ator means, means for providing a control signal depending on whether or not an electric field intensity of a receiving signal exceeds a predetermined value, and first means between said directional coupler means and said detector means for varying the power applied from said power amplifier means via said directional coupler to said detector means in response to said control signal, thereby extending the controllable range for output power of said radio transmitter.
2. A radio transmitter as claimed in claim 1 wherein said directional coupler means has a coupling point and said first means comprises a capacitor and means responsive to said control signal for coupling therethrough said capacitor between said coupling point and a potential point.
3. A radio transmitter as claimed in claim 1 wherein said directional coupler means has a coupling point and said first means comprises a second means coupled between said directional coupler means and said detector means for attenuating the power applied from said directional coupler means to said detector means.
4. A radio transmitter as claimed in claim 3, wherein said second means comprises a plurality of PIN diodes.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1980001542U JPS6110327Y2 (en) | 1980-01-10 | 1980-01-10 | |
| JP1542/1980 | 1980-01-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1164054A true CA1164054A (en) | 1984-03-20 |
Family
ID=11504405
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000368156A Expired CA1164054A (en) | 1980-01-10 | 1981-01-09 | Radio transmitter having an output power control circuit |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4392245A (en) |
| JP (1) | JPS6110327Y2 (en) |
| AU (1) | AU539884B2 (en) |
| CA (1) | CA1164054A (en) |
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| JP5327324B2 (en) * | 2009-12-18 | 2013-10-30 | 株式会社村田製作所 | Directional coupler |
| RU2463704C1 (en) * | 2011-06-22 | 2012-10-10 | Открытое акционерное общество "Государственный Рязанский приборный завод" (ОАО "ГРПЗ") | Microwave transmitter with optimal setting of output capacity |
| RU2480906C1 (en) * | 2011-09-21 | 2013-04-27 | Открытое акционерное общество "Государственный Рязанский приборный завод" (ОАО "ГРПЗ") | Highly secure microwave transmitter |
| RU2538908C2 (en) * | 2012-12-20 | 2015-01-10 | Российская Федерация, от имени которой выступает Министерство обороны Российской Федерации | Method of stabilising travelling-wave tube (twt) parameters when tuning microwave transmitter |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3641451A (en) * | 1970-02-24 | 1972-02-08 | Motorola Inc | Amplifier protection circuit |
| US3662290A (en) * | 1970-08-05 | 1972-05-09 | Collins Radio Co | Automatic control for amplitude-modulated signal source |
| US3715690A (en) * | 1971-05-18 | 1973-02-06 | Trw Inc | Automatic tuning electric wave filter |
| US3866136A (en) * | 1973-04-23 | 1975-02-11 | Motorola Inc | Amplifier protection circuit |
| GB1480400A (en) * | 1974-07-13 | 1977-07-20 | Marconi Instruments Ltd | Signal generators |
| US4044308A (en) * | 1976-09-20 | 1977-08-23 | Gte Sylvania Incorporated | Communication transmitting apparatus with carrier level control |
| US4165493A (en) * | 1978-04-17 | 1979-08-21 | Rockwell International Corporation | Protected amplifier apparatus |
-
1980
- 1980-01-10 JP JP1980001542U patent/JPS6110327Y2/ja not_active Expired
- 1980-12-22 US US06/218,477 patent/US4392245A/en not_active Expired - Lifetime
-
1981
- 1981-01-06 AU AU66010/81A patent/AU539884B2/en not_active Ceased
- 1981-01-09 CA CA000368156A patent/CA1164054A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| AU6601081A (en) | 1981-07-16 |
| JPS56104204U (en) | 1981-08-14 |
| US4392245A (en) | 1983-07-05 |
| JPS6110327Y2 (en) | 1986-04-03 |
| AU539884B2 (en) | 1984-10-18 |
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