JPH0773222B2 - Stabilized transmitter - Google Patents

Description

TECHNICAL FIELD The present invention relates to a stabilized transmitter used in a microwave communication device.

2. Description of the Related Art Generally, a high frequency transmitter of a microwave communication device is required to have high gain stability including temperature characteristics.

A conventional example will be described below with reference to the drawings. Fifth
The figure shows a circuit block diagram of a conventional transmitter. Reference numeral 1 is an up-converter, 2 is a variable attenuator whose attenuation is changed by a DC voltage applied to a terminal 15, 3 is a semi-fixed attenuator whose volume is changed by changing an applied voltage, and 4 is an up-converter unit, 5 is a solid state power amplifier using a semiconductor [SSPA: Solid State Power Amp
lifier] power amplifier, 6 is a voltage generation circuit for detecting the temperature of SSPA5 and correcting the temperature change of the gain of SSPA5 by the variable attenuator 2, 7 is an SSPA unit, and 8 is a local oscillator.

In the operation of the transmitter configured as described above, the intermediate frequency signal is applied to the terminal 9, the local oscillation signal applied to the terminal 10 is mixed with the up-converter 1, and the high frequency signal appears at the terminal 11. It is input to the input terminal 12 of the SSPA5, amplified in power, output to the output terminal 13 as a transmission carrier, and sent to the antenna system.

Here, in SSPA5, generally, the value of the gain at room temperature and the amount of temperature change vary during manufacturing, so this variation must be absorbed by some method.

The stabilization of the transmission gain is performed as follows. As shown in FIG. 6, the up-converter unit linearly changes the conversion gain with respect to the external input voltage and turns the volume to change the conversion gain. The gain slope with respect to this external input voltage is δ _UC (= ΔG _UC / ΔV), which is sufficiently stable with respect to temperature.

On the other hand, the SSPA has a built-in temperature sensor, measures the temperature characteristic of the gain G _A of the SSPA, and obtains the temperature coefficient τ _A (= −ΔG _A / ΔT) of the gain. Since the condition for temperature correction is given by the equation (3) described in the following embodiment, τ _V (= Δ) that satisfies this equation
The gain temperature change correction circuit 6 is adjusted so that a DC voltage having V / ΔT) is output. Here, since each τ _{A of} SSPA varies as shown in FIG. 7A, τ _V has a slightly different value for each as shown in FIG. 7B. The solid line and broken line characteristics in FIG. 7 correspond to each other.

Next, the upconverter and the SSPA are connected, and the transmission gain G _TX between the input end of the upconverter and the output end of the SSPA is measured at room temperature. For example, when this measured value is larger than the required value by ΔG. , Adjust the gain of the semi-fixed attenuator 3 in the up-converter by ΔG as shown in FIG.
Adjust so that the _TX value is the required value.

However, in the above configuration, when the upconverter unit or the SSPA unit fails and the unit is replaced, the transmission gain is remeasured and the semi-fixed attenuator in the upconverter unit is re-measured. There is a problem in that the gain must be measured twice when manufacturing the transmitter.

In view of the above-mentioned problems, the present invention provides a stabilized transmission device that does not require re-adjustment when replacing a unit and requires only one gain measurement when manufacturing a transmitter.

Means for Solving the Problems In order to solve the above problems, the stabilized transmission device of the present invention is
A variable attenuator whose attenuation is changed by an external DC voltage is installed in the up-converter unit, while a temperature sensor is built into the SSPA to measure the temperature characteristic of the gain of the power amplifier. A DC voltage that takes a value that corrects the difference between the required value and the measured value of the gain of the power amplifier by the up converter and that changes when the ambient temperature changes so as to correct the gain change of the power amplifier by the up converter. Is provided, and the DC voltage is input to the up converter.

Effect The present invention has the above-described configuration, and at the time of manufacturing, measures the temperature characteristic of the gain of SSPA, and takes a value for correcting the difference between the required value and the measured value of the gain of the power amplifier at the same temperature by the up converter. Also, when the ambient temperature changes, by inputting a DC voltage that changes so as to correct the gain change of the power amplifier in the up converter, it is possible to increase even when the gain of SSPA at room temperature is different during manufacturing. The transmission gain, which is the sum of the conversion gain of the converter and the gain of the power amplifier, can be constant regardless of the ambient temperature, and readjustment is not required when the upconverter unit or SSPA unit is replaced. Further, the gain measurement at the time of manufacturing the transmitter can be performed only once.

Embodiment Hereinafter, a stabilized transmission device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a circuit block diagram of a stabilized transmitter according to an embodiment of the present invention, and FIGS. 2, 3, and 4 are characteristic diagrams of respective portions of FIG. In FIG. 1, 16 is an up-converter,
Reference numeral 17 is a variable attenuator whose attenuation changes according to the DC voltage applied to terminal 29, and 18 is an up-converter unit consisting of up-converter 16 and variable attenuator 17, where the conversion gain is sufficiently stable with respect to ambient temperature and external It is assumed that it has a characteristic that changes linearly with respect to a DC voltage. 19 is the power amplification part of the SSPA, and 20 is a value according to the difference between the measured value of the SSPA 19 at room temperature and the required value at room temperature.When the temperature changes, the temperature change of the gain is corrected by the built-in temperature sensor. A circuit that generates a DC voltage that changes linearly at terminal 28, 21 is SSPA19
It is an SSPA unit consisting of a gain correction DC voltage generation circuit 20. The above-described temperature-stable up-converter unit can be realized by using a temperature sensitive element such as a thermistor for the PIN diode attenuator. FIG. 2 shows the input voltage V of the up converter unit 18.
Figure 3 (a) shows the characteristics of the conversion gain G _UC for SSPA19
5B is a characteristic diagram of the gain G _A with respect to the ambient temperature T, and FIG. 7B is a characteristic diagram of the gain correction voltage V with respect to the ambient temperature T. Fourth
The figure is a characteristic diagram of the transmission gain G _TX (= G _UC + G _A ).

It should be noted that symbols 1 and 2 in FIGS. 3 and 4 respectively show two cases in which the measured values of the gain of SSPA at room temperature are different from G _A0 and G _A0 + ΔG.

The operation of the stabilized transmitting device configured as described above will be described below.

The required gain of SSPA19 is G _A0, and the conversion gain of the up converter at this time is G _UC0 .

First, when the measured value of gain G _A of SSPA19 is ambient temperature
Consider the case of G _A0 (basic case). At room temperature, the DC voltage value is output from the gain temperature correction circuit according to Fig. 3 (b).
V _O is output, and at this time, the conversion gain of the up-converter becomes G _UC0 according to FIG. That is, the transmission gain at room temperature is G _TX (T _O ) = G _UC0 + G _A0 .

When ambient temperature changes, SSPA gain is generally negative temperature coefficient τ
Has _A, the temperature characteristic is as shown in FIG. 3 (a).
In addition, this value varies with each SSPA. Therefore, each temperature coefficient τ _A of SSPA is measured, and the temperature of the device is detected by the temperature sensor to cancel the temperature change amount according to the following equation (3), and the characteristic of (b) in the figure is obtained. Generates DC voltage. The temperature coefficient of this DC voltage is τ _V. Then, the method of obtaining τ _V is as follows. The transmission gain G _TX is expressed by the following equation in the system shown in FIG.

G _TX (T) = G _UC [V (T)] + G _A (T) (1) From the equation (1), the temperature coefficient of G _TX is Becomes Therefore, by setting τ _V so that δ _UC · τ _V = τ _A (3) That is, the transmission gain can be made constant regardless of the ambient temperature.

Next, when the measured value of the gain G _A of SSPA is G _A0 + ΔG at room temperature, the correction voltage output from SSPA is shifted by −ΔV as compared with the above basic case as shown in FIG. 3 (b). This corresponds to the case where T = T _O and the variable attenuator 17 performs the gain correction of the gain deviation ΔG from the above basic case. At this time, the transmission gain G _TX0 is expressed by the equation (1) with G _A (T _O ) = G _A0 + ΔG, V (T _O ) = V _O −ΔV, G _UC (V _O −ΔV) = G _UC0 −ΔG Substituting (5), G _TX0 = G _TX (T _O ) = G _UC [V (T _O )] + G _A (T _O ) = G _UC (V _O −ΔV) + G _A0 + ΔG = G _UC0 − ΔG + G _A0 + ΔG = G _UC0 + G _A0 (6) (Fig. 4). The temperature characteristics of the transmission gain can be stabilized in the same manner as in the above-mentioned basic case (Figs. 3 (a), (b) and symbol 2 in Fig. 4). Therefore, even when the SSPA gains differ at room temperature, the transmission gain is always constant regardless of the temperature.

As described above, the present invention has a function in which the conversion gain is changed by an external DC voltage in the up-converter unit, while the power amplifier incorporates a temperature sensor and the temperature of the gain of the SSPA is increased. The characteristic is measured, and at normal temperature, the up converter corrects the difference between the required value and the measured value of the gain of the power amplifier at the same temperature, and when the ambient temperature changes, the gain of the power amplifier is increased by the up converter. A circuit for outputting a DC voltage that changes so as to correct a change is provided, and by the configuration in which the DC voltage is input to the up converter, even when the gain of the SSPA unit varies during manufacturing, the up converter unit and the In any combination of SSPA units, the transmission gain remains constant regardless of ambient temperature, Tayunitto has an excellent effect that gain readjustment when failed to module change only once the measurement of the gain at the transmitter manufactured with unnecessary.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of a stabilized transmitter according to an embodiment of the present invention, FIGS. 2, 3, and 4 are characteristic diagrams of each part of FIG. 1, and FIG. 5 is a block of a conventional transmitter. FIG. 6, FIG. 6 and FIG. 7 are characteristic diagrams of each portion of FIG. 1,16 …… Up converter, 2,17 …… Voltage control variable attenuator, 3 …… Semi-fixed variable attenuator, 4,18 …… Up converter unit, 5,19 …… SSPA, 7,21 …… SSPA Unit, 6
...... Gain temperature change compensation circuit, 20 …… Gain compensation circuit, 8,22
...... Local oscillator.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Mohri 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-62-203429 (JP, A)

Claims (1)

[Claims] 1. A transmitter comprising an up converter for converting an intermediate frequency signal into a high frequency signal by using a local oscillation signal and a power amplifier for amplifying the power of the high frequency signal, wherein the up converter has a conversion gain from an external direct current. The power amplifier has a function of changing with voltage, while the power amplifier has a built-in temperature sensor and measures the temperature characteristic of the gain of the power amplifier.
At room temperature, the up-converter corrects the difference between the required value and the measured value of the gain of the power amplifier at the same temperature, and when the ambient temperature changes, the up-converter corrects the gain change of the power amplifier. And a circuit for outputting a DC voltage that changes as described above, the DC voltage is input to the up-converter, and the conversion gain of the up-converter and the gain of the power amplifier are different even when the gain at room temperature of the power amplifier is different at the time of manufacturing. A stabilized transmission device in which the transmission gain, which is the sum of the above, is constant regardless of the ambient temperature.