JPS63156431A - Power switching type amplifier - Google Patents

Abstract

PURPOSE:To enable power to be switched corresponding to the presence/absence of fading, etc., and to prevent adverse effect(for example, generation of hit) from being given on a signal to be transmitted at the time of switching the power, by providing a bypassing part having a variable phase shifter controlled by an in-phase synthesizing control part in the inside in parallel with the part. CONSTITUTION:When the power is saved, that is no fading, etc., is generated, power saving is performed by setting an amplifier part 31 as a non-driving part, and also, after an input signal Sin is introduced to the bypassing part 32, it is set as an output signal Sout. In a transient time when a normal operation is switched to a power saving operation, or vice versa, a normal output (output via the amplifier part 31) is mixed transiently with a power saving output (output via the bypassing part 32) on the output side of a switching part 34 at a rear stage. It offers no problem if the above mixing is performed with in-phases with each other, but it is inevitable to prevent phase shift from occurring, Therefore, the phase shift is detected by a detecting part 35, and the in-phase synthesizing control part 36 controls the variable phase shifter 37 so as to reduce the phase shift to zero according to detected phase shift. Thus, it is possible to prevent the phase shift from being generated, and to perform the switching of the power without generating the hit at the time of switching the an operation from the normal operation to the power, saving operation, or vice versa.

Description

[Detailed Description of the Invention] [Summary] This is a power switching amplifier, in which a bypass section is provided in parallel to an amplification section that amplifies the power of an input signal. At the same time, the phase shift between the normal output and the power saving output during the transition period between normal and power saving mode is detected, and a certain control is applied to By in-phase combining the output during power saving and the output during power saving, switching between the power saving mode and normal mode is performed without momentary interruption.

[Industrial application field]

The present invention relates to a power switching amplifier, and particularly to a power switching amplifier suitable for application to a transmission stage of a digital microwave radio device.

The transmission stage of microwave radio equipment is equipped with a high-frequency, high-output amplifier, but this amplifier consumes about half of the power of the entire radio equipment, especially in microwave radios that can only be powered by batteries. There is a strong demand for low power consumption in relay stations.

[Conventional technology]

FIG. 6 is a diagram showing a general configuration of a microwave wireless communication system. In this figure, the microwave wireless communication system is roughly divided into a transmitting system 10 in the upper stage and a receiving system 20 in the lower stage, and the two are connected by an antenna 15 and an antenna 2N21''J through space propagation. , each wireless relay station has a pair of transmitting system and receiving system, and performs uplink and downlink data transmission, but in this figure,
For simplicity, only one of the uplink and downlink systems is shown.

The transmission system 10 transmits transmission data Ds to be transmitted through an interface (INT) 11 , a modulator (gate 00) 12 , a transmitter (Tx) 13 having an up-converter, a high frequency/high output amplifier (HPA) 14 and an antenna 15 . The data is sent to the transmission system 20 via the transmission system 20. The present invention is directed to the amplifier 14 of these
Let's talk about.

On the other hand, in the receiving system, signals from the transmitting system 10 are received by antennas 21 and 21', and after passing through receivers (Rx, 5D-Rx) 22 and 22' having down converters, they are combined in a combiner 23. Note that the antenna 21',
The receiver 22' is for constructing space diversity (SD). The signal from the synthesizer 23 is sent to a demodulator (OEM) 24 and a transversal equalizer (TE).
QL) 25, analog/digital converter (A/D) 26, interface (INT) 2 for data identification
7, the received data D and l are obtained.

By the way, in the spatial propagation between the antenna 15 and the antennas 21 and 21', propagation loss occurs due to various factors. A typical example is fading. When fading occurs, the quality of the received signal in the receiving system 20 is significantly degraded. Therefore, in -g, the transmit signal is amplified by a relatively large power that can cover the fading time in the amplifier 14, and then sent to the receiving system 20. Processing such as demodulation is performed after reducing the received power. The AG is responsible for narrowing down the received power.
C (Automatic Galn Control)
This is an amplifier, and is placed, for example, at the position indicated by 28 in the figure.

[Problem that the invention seeks to solve]

As described above, the receiving system 20 uses the received power in a limited manner, and operates the AGC amplifier 28 at full gain only when fading occurs. Therefore, the amplifier 14 in the transmission system 10 amplifies the power of the transmitted signal with a high output that can always cope with fading with a low degree of occurrence, regardless of whether it is fading or normal (when there is no effect of fading etc.). I am going to do it,
There is a problem in that it is a serious hindrance to power saving. Incidentally, the annual time ratio between the above-mentioned normal state and the above-mentioned fading state is statistically about 97% to 3%.

The present invention has been made in view of the above problems, and it is possible to switch the power depending on the presence or absence of fading, etc., and to avoid adversely affecting the signal to be transmitted (for example, generation of instantaneous interruptions) at the time of switching (low-power signal It is an object of the present invention to provide a power switching amplifier capable of switching from high power signals to high power signals and vice versa.

[Means for solving problems]

FIG. 1 is a principle block diagram of a power switching amplifier according to the present invention. In this figure, the power switching type amplifier 30 has an amplifying section (AMP) 31 as its core, and has a bypass section 32 provided in parallel with this.

A variable phase shifter 37 is included within the bypass section 32 .

The bypass section 32 is also connected to a front-stage switching section (SWi) 33 and a second-stage switching section (SWo) 34 provided on the input side and output side of the amplification section 31, respectively. Bypass section 32
The variable phase shifter 37 within is controlled by an in-phase synthesis control section 36, and its control input is generated by a detection section 35.

[For production]

In normal times when the original power amplification should be performed, that is, when fading etc. occur, the input signal Sin is
1 and becomes the output signal 5out. In this case, the front-stage switching section 33 and the rear-stage switching section 34 pass the input signal from the left to the right in the figure.

On the other hand, when power is being saved, that is, when fading or the like is not occurring, the amplifier section 31 is not driven to save power, and the input signal Sin is guided to the bypass section 32 and then outputted as an output signal 5out. In this case, the front-stage switching section 33 switches the input signal Sin to the lower side in the figure, and the rear-stage switching section 34 selectively passes the signal from the bypass section 32 side to the output signal 5out.

During the above-mentioned transitional period of switching from the normal state to the power saving state and vice versa, the output side of the latter stage switching section 34 temporarily outputs the normal state (
The power saving output (output via the amplifying section 31) and the power saving output (output via the bypass section 32) are mixed. There is no problem if this mixing is done in phase with each other, but in reality, mutual phase shifts are unavoidable. Therefore, the detection section 35 detects the phase shift, and according to the detected phase shift, the in-phase synthesis control section 36 controls the variable phase shifter 37 so as to make the phase shift zero. In this way, switching from normal mode to power saving mode or vice versa can be performed without any phase shift and without any interruption.

〔Example〕

FIG. 2 is a diagram showing an embodiment of the power switching type amplifier according to the present invention. In this figure, the same reference numbers or symbols are attached to the same components as those already described (hereinafter, the same applies). Looking at the correspondence with FIG. 1, the amplifier section 31 in FIG. 1 corresponds to the cascade amplifier 41 in FIG. )42 and fixed delay, I
(OL) 42', and the front stage switching section 33 is, for example, a PI
This corresponds to a switching element 43 such as an N diode and a circulator 43', and the subsequent switching section 34 similarly corresponds to a switching element 44 and a circulator 44'.
The detection section 35 corresponds to a bandpass filter (BPF) 45 and a detector 45', and the in-phase synthesis control section 36 corresponds to a processor 46. The controller 48 controls the overall timing, etc., and mainly controls the switching element 43.
, 44 and on/off control of the amplifier 41. Preferably, controller 48 is driven by a service channel signal SC from receiver board 49. This service channel signal SC is a normal signal carried on the downlink from the other party's relay station, and this signal SC includes information (2) indicating the quality of the spatial propagation situation. That is, if fading or the like occurs, the signal SC from the other party's relay station will indicate a deterioration in the spatial propagation situation. When there is information indicating this deterioration, the controller 48 turns on the switching element 43;
Switching element 44 is turned off. Furthermore, the cascade amplifier 41 is activated to amplify the input signal Sin that has passed through the element 43 with high power. For example, bias voltage vl
supply. Note that since the switching elements 43 and 44 are always turned on and off in a complementary manner, an inverter 52 is provided.

Now, the switching element 44 is off, and the signal input to the circulator 44' once reaches the element 44, where it is reflected and returns to the circulator 44' again.
The output signal becomes 5out. The circulator 44' is effective in preventing signals from going around to the output side of the cascade amplifier 41. Thus, during normal times when the cascade amplifier 41 is to be driven, the bypass section (42, 42') is in a rest state.

By the way, assuming that fading and the like have disappeared and the spatial propagation situation has become favorable, the output signal 5out can be received fairly well by the other party without amplifying the input signal Sin to a high power. Therefore, while the cascade amplifier 41 is stopped, the bypass section (42, 42') is used to output the input signal Sin to the output signal 5out without power amplifying it. This is the operation when saving power.

During this power saving period, since no fading or the like has occurred, the service channel signal SC does not include information (2) indicating deterioration of the spatial propagation condition. Then, the controller 48 turns off the switching element 43, turns on the switching element 44, and turns on the cascade amplifier 4.
The supply of the high-ass voltage 6 to the cascade amplifier 41 is cut off, and the cascade amplifier 41 is not driven. In this case, the input signal Sin passes through the circulator 43', reaches the element 43 (which is turned off), is reflected here, and returns to the circulator 43'.
3' and then reaches the delay line 42'.

Furthermore, endless phase shifter 42 and element 44
(which is turned on) and the output signal 5out via the circulator 44'. The circulator 43' at the front stage is effective in preventing unnecessary signals from being transmitted from the bypass section 42 side to the human power of the cascade amplifier 41.

As mentioned above, when saving power, the input signal Si passes through the bypass sections 42 and 42', and only during normal times, the input signal Si passes through the cascade amplifier 41.
The power switching type amplifier 30 is realized by performing power amplification of n. However, a problem arises during the transition period when switching from normal mode to power saving mode or vice versa.

FIG. 3 is a graph for explaining the switching situation between normal times and power saving times, where the horizontal axis is time and the vertical axis is loss. curve 4
3 relates to the switching element 43.

Curve 44 relates to switching element 44 . During power saving, the element 43 is off and the loss is large, and the element 44 is on and the loss is small. Conversely, under normal conditions, element 43 is on and the loss is small.
When the element 44 is off, there is a large loss. In the switching transition period between these elements, elements 43 and 43 exhibit an intermediate loss. That is, in the hatched area in this figure, the normal output (output via the cascade amplifier 41) and the power saving output (output via the bypass sections 42, 42') are mixed. At this time, there is no problem if the normal output and the power saving output are mixed in the same phase, but in reality, a mutual phase shift occurs between the two. Such a phase shift is
Particularly when transmitting extremely large amounts of data, such as multilevel QAM, data errors will occur, so it is necessary to reduce the deviation to almost zero.

An endless phase shifter 42 is provided to reduce the above phase shift to zero, and here the bypass section 42,
The phase of the input signal Sin passing through 42' is matched with the phase of the input signal Sin passing through the cascade amplifier 41. In this case, it is advantageous to compensate for the phase shift caused by passing through the cascade amplifier 41 in advance by means of a fixed delay line 42'. In this way, the amount of phase adjustment by the shifter 42 can be kept within a small range.

The above phase shift can be detected by various methods, but in the embodiment of the present invention, it is detected from the frequency spectrum of the output signal 5out. For this reason, first, in the band pass filter 45, the low range (frequency r+) and the middle range (frequency rz)
, each frequency component in the high range (frequency r3) is extracted, and each power is detected by the corresponding diode detector 45'. FIG. 4 is a graph showing an example of a frequency spectrum detected by the detection unit, where the horizontal axis represents frequency and the vertical axis represents power. The graph in this figure is a normal case, and the lines connecting the vertices (f+, z, fs) of the graph are horizontal. However, during the transition period between the normal state and the power saving state, the above-mentioned phase shift occurs and the horizontal line cannot be maintained.

Therefore, the ROM (Read
The frequency spectrum of the output signal 5out during normal operation is recorded in advance in the 0nly Memory), and compared with the frequency spectrum obtained through the bandpass filter 45 and the detector 45'. If, for example, a -th order slope is found in the detected frequency spectrum, a control signal is calculated within the processor 46 to return it to horizontal, and the phase shifter 42 is controlled using this control signal. Here, switching from one output to the other is performed smoothly while preventing a phase shift between the normal output and the power saving output. Therefore, the above-mentioned data error will not occur during this switching transition period.

FIG. 5 is a diagram showing an example of generation of information to be carried on a service channel signal. As described above, the service channel signal SC includes information I indicating the quality of the spatial propagation situation. This information (■) is generated at the other party's relay station. In other words, if the reception condition deteriorates due to fading or the like, information 11 is generated. However, the information (2) is not limited to always being supplied from the other party's station, and may be generated within the own station. If the reception condition at the own station becomes poor, it is determined that the reception condition at the other station using the same spatial propagation path has also become poor, and the information (2) is generated by itself and given to the controller 48 (Fig. 2). It is. However, in this case, it is not a direct method of asking the other party to judge whether the reception status of what you have transmitted is good or bad (rather, it is an indirect judgment, so the transmission frequency is slightly different between the uplink and downlink). (The effect of fading is slightly greater), it is more accurate to have the information generated by the other party sent on the service channel signal SC.In Fig. 5, the AGC amplifier 28 is the same as shown in FIG. 6, and is the AGC amplifier of the other station.The AGC amplifier 28 is the cascade amplifier 51, 5
2, attenuators 53 and 54, a comparator 55, and an integrator 56, and this amplifier 28 itself has a general configuration. The output of the cascade amplifier 52 is taken out by a detector 57, its level fluctuation is detected by a comparator 55, and a certain degree of integration is performed.
Adjust the attenuation amount in step 4 and perform AGC. Therefore, the output of the integrator 56 is branched and guided to a level detector 58, where the magnitude of the AGC control voltage is detected. If the AGC control voltage is small and the attenuation amount of the attenuators 53 and 54 is large, it means that the spatial propagation situation is good and it is not enough to send out information 1. On the other hand, the AGC control voltage is large,
If the attenuation amount of the attenuators 53 and 54 is small, it means that the spatial propagation situation has worsened, and information (2) is output. This is transmitted to the own station on the service channel signal SC.

〔Effect of the invention〕

As explained above, according to the present invention, power switching is performed in two stages, that is, passing through the amplifier section or passing through the bypass section,
In particular, when fading is not occurring (which is the case most of the year), the bypass section is used, so the power saving effect is extremely large.

At this time, since the above-mentioned phase control is taken into consideration when switching between the bypass section and the amplification section, problems such as data errors do not occur.

[Brief explanation of the drawing]

Fig. 1 is a principle block diagram of the power switching amplifier according to the present invention, Fig. 2 is a diagram showing an embodiment of the power switching amplifier according to the invention, and Fig. 3 shows the switching status during normal and power saving times. Graphs for explanation: Figure 4 is a graph showing an example of a frequency spectrum detected by the detection unit; Figure 5 is a diagram showing an example of generation of information to be added to a service channel signal; Figure 6 is a microwave wireless communication system. FIG. 2 is a diagram showing a general configuration of. 31... Amplification section, 32... Bypass section, 3
3... Front stage switching section, 34... Back stage switching section, 35.
...detection section, 36... in-phase synthesis control section. Figure 2 shows an example of the frequency spectrum detected by the loss switching transient power detection unit Figure 4 shows an example of the generation of information to be added to the service channel signal Figure 5 General configuration Figure 6

Claims (1)

[Claims] 1. An amplifier section (31) that outputs an output signal (Sout) obtained by power amplifying the input signal (Sin) during normal operation, and is not driven during power saving, and an input of the amplifier section (31). Between the front-stage switching section (33) and the rear-stage switching section (34), which are provided on the side and the output side and perform switching between the normal state and the power-saving state, and the front-stage and second-stage switching sections (33, 34), the Amplification section (31
), and includes a variable phase shifter (37) and allows the input signal (Sin) to pass during the power saving period, and a bypass section (32) that is connected in parallel with the energizing state to the power saving state or vice versa. During the transition period, the amplifier (31
); and a detection unit (35) that detects a phase shift between the normal output from the bypass unit (32) and the power saving output from the bypass unit (32); A power switching amplifier characterized by comprising an in-phase synthesis control section (36) that synthesizes the power-saving output in the same phase.