JPH0514255A - Radio transmitter-receiver - Google Patents

Abstract

PURPOSE:To improve the linearity of an power amplifier at a final stage by providing a stabilized power supply which generates a voltage higher than that of a battery, and supplying the generated voltage to the power amplifier at the final stage. CONSTITUTION:A stabilized power supply 1 receives the supply of an energy from a power source(battery) 6, generates the voltage higher than that of the power source 6, and supplies it to a power amplifier 2. The stabilized power supply 1 is that of an Up-Converter system, and for example, a voltage conversion can be efficiently operated by using a switch regulator of a step-up/down type using a PWM(Pulse Width Modulation). Thus, a linear amplification can be attained in the wider range of an output power level. Therefore, a communication in which the enlargement of a spectrum can be suppressed without any adjacent channel disturbance is attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio transmitter / receiver used for mobile communication and the like.

[0002]

2. Description of the Related Art Generally, wireless transceivers for mobile communication are driven by batteries. For example, an in-vehicle car phone uses a car battery (13.8V), and a so-called mobile phone uses a 6V Ni-Cd battery or the like.

In a radio transmitter / receiver, a power amplifier (hereinafter referred to as PA) is provided at the final stage in order to send radio waves from an antenna.
The current consumption of the PA occupies more than half of the current consumption of the wireless transceiver. Therefore, the power supply terminal of the PA is often directly connected to the battery in order to obtain sufficient output power and to minimize the loss in the power supply system.

As a power source for parts other than the PA,
After stabilizing to a predetermined voltage, it is supplied to each part. Regarding the type of voltage, the wireless transceiver may constitute a negative voltage power supply.

FIG. 2 is a block diagram showing a part of the above-mentioned conventional radio transceiver, showing the relationship between the power amplifier (PA) 2 and the power source (battery) 6. Inside PA2, the collector (Tr) and drain (FET) of the amplification element
The power source 6 is connected to.

[0006]

However, in the radio transmitter / receiver having the above structure, the linearity of the transmission PA becomes insufficient because the voltage of the power supply (battery) is low, the transmission spectrum is widened, and the adjacent channels are disturbed. There was a problem that would end up.

The present invention solves the above-mentioned problem of spectrum expansion due to nonlinear distortion of the transmission PA.
It is an object of the present invention to provide an excellent wireless transceiver without adjacent channel interference by using a stabilized power supply of Up-Convert system as a power supply of PA.

[0008]

In order to achieve the above object, the present invention provides a battery-operated radio transceiver, which is provided with voltage generating means for generating a voltage higher than the voltage of the battery, and which voltage is generated at the final stage. Power amplifier.

[0009]

The power amplifier in the final stage operates at a voltage higher than the voltage of the battery, so that linear amplification can be performed even when the output voltage level is high.

[0010]

1 is a block diagram showing an embodiment of the present invention.
In FIG. 1, 5 is a wireless transceiver, 6 is a power source (battery),
Reference numeral 7 denotes an antenna, and the wireless transceiver 5 receives energy supplied from a power source 6 and radiates radio waves from the antenna 7 into the air.

In the radio transmitter / receiver 5, 1 and 3 and 4 are voltage stabilizing circuits, and 2 is a power amplifier (PA), and parts which are not directly related to the present invention are omitted. The voltage stabilizing circuit 1 is a stabilized power supply of the Up-Converter system, receives energy supply from the power supply 6, generates a voltage higher than the voltage of the power supply 6, and supplies the voltage to the power amplifier 2. Therefore, the power amplifier 2 can be operated by a power supply having a voltage higher than the voltage of the power supply 6, so that the linearity is greatly improved as compared with the conventional case.

FIGS. 3 and 4 show an example of the input / output characteristics of SiMosPA in a radio transceiver of 800 MHz band for automobile telephones. FIG. 3 shows the case where the power supply voltage supplied to SiMosPA is 15V. Power supply voltage is 11V
Is the case. Comparing FIG. 3 and FIG. 4, it can be seen that the input / output characteristic of FIG. 3 has much better linearity than the input / output characteristic of FIG. 4, and the linearity is improved by increasing the power supply voltage. Shows. Therefore, the present invention is very effective when applied to a digital cellular car telephone or the like which requires linear amplification.

The Up-Converter type stabilized power supply shown in FIG. 1 is, for example, a PWM (Pul) as shown in FIG.
By using a step-up / down type switching regulator (Motorola Co.) using se width modulation, a stabilized power supply with extremely low loss can be configured.

Further, generally, in mobile communication such as a car telephone, the output power of the mobile device is controlled in multiple stages according to the distance from the base station. In this case, it is effective to set the power supply voltage of the power amplifier to have the best linearity according to the output power level.

Therefore, in the embodiment shown in FIG. 1, it is not necessary to fix the voltage of the power source supplied to the PA 2 to a voltage higher than the voltage of the battery 6, and it is possible to change the voltage according to the output power. Setting a voltage value smaller than the battery voltage is useful for obtaining linearity in a wide range of the amplifier.

Furthermore, the voltage stabilizing action of the stabilized power supply can prevent the spectrum from being spread due to the phase modulation due to the fluctuation of the power supply voltage due to the change of the amplitude of the transmission RF signal.

The voltage stabilizing circuits 3 and 4 shown in FIG. 1 supply a power source stabilized to a required voltage value to each unit in the wireless transceiver 5. Here, the voltage to be supplied is generally set to a voltage value lower than the voltage of the power supply 6. Further, in the present embodiment, the number of power supply stabilizing circuits is two, but the number is not limited to this.

[0018]

As described above in detail, according to the present invention, a voltage higher than the battery voltage can be supplied as the power supply voltage to the power amplifier, so that linear amplification can be performed in a wider range of the output power level. become. Therefore, it is possible to perform communication without the interference of adjacent channels while suppressing the spread of the spectrum.

Further, by using an up / down type switching regulator as the stabilized power supply, the voltage conversion can be efficiently performed.

Further, by varying the voltage to the power amplifier according to the output power level and setting it, the linearity can be optimally set at each output power level.

The present invention is designed for digital signals requiring linear amplification.
It is effective for cellular car phones, etc.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional wireless transceiver.

FIG. 3 is an input / output characteristic diagram of the power amplifier (power supply voltage 15V).
Is.

FIG. 4 is an input / output characteristic diagram of the power amplifier (power supply voltage 11 V).
Is.

FIG. 5 is a circuit diagram of a step-up / down type switching regulator.

[Explanation of symbols]

1 Up Converter stabilized power supply 2 power amplifier 3,4 Voltage stabilization circuit 5 wireless transceiver 6 power supply (battery) 7 antenna

Claims (3)

[Claims] 1. In a wireless transceiver operating on a battery,
A radio transmitter / receiver characterized by comprising voltage generating means for generating a voltage higher than the voltage of the battery, and supplying the generated voltage to a final stage power amplifier. 2. The wireless transceiver according to claim 1, wherein the voltage generating means is an up / down type switching regulator. 3. The radio transceiver according to claim 1, wherein the voltage generating means has means for changing the output voltage according to the output power level of the power amplifier.