JPH1146160A - Radio relay amplifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the radio relay amplifier installed at a dead band that satisfies tight requirements for out-band attenuation at a transmission reception frequency band. SOLUTION: An outgoing amplifier section 3 (incoming amplifier section 4) is provided with an intermediate frequency stage 32(46) to convert a high frequency RF (900 MHz) into an intermediate frequency IF (90 MHz) to increase an attenuation gradient of a filter. In the intermediate frequency stage 32, a non-polar BPF 37, a polar LPF 39 and a polar HPF 40 are connected in cascade, the intermediate frequency component is selectively amplified, the increase in loss is suppressed and a low noise amplifier section 31 and a high power amplifier section 33 maintain a noise figure and a high output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio relay amplifying apparatus which is arranged in a blind area to improve service in a mobile communication system.

[0002]

2. Description of the Related Art In public mobile communications such as cellular phones, consideration is given to minimizing blind areas. In other words, in order to reliably provide services in areas affected by terrain and buildings, in areas that are far from the base station, or in insensitive areas such as underground shopping malls and tunnels where radio waves from the base station are difficult to reach, A wireless relay amplifying device that bidirectionally amplifies radio waves between mobile stations is arranged.

FIG. 3 is a block diagram of a conventional wireless relay amplifier. In the figure, 1 is an antenna for a base station, 12 is a duplexer, 13 is a down-amplifying unit that relays and amplifies a downlink signal from a base station to a mobile station, and 14 is an uplink amplifying unit that relays and amplifies an uplink signal from a mobile station. , 15 are duplexers and 6 is a mobile station antenna.

[0004]

However, in recent years, GSM (Global System) has been adopted as a European unified standard system for digital mobile phones.
System for Mobile Communications) standards have been defined, and detailed specifications for the pass frequency bands of outgoing and uplink signals and out-of-band gain (attenuation) have been defined in the specifications of the wireless relay amplifier. FIG. 4 is a diagram showing an example of the out-of-band attenuation characteristic specification showing an example of the specification, and an extremely steep characteristic of the attenuation gradient is required.

This standard is a standard for a mobile transmission frequency band in a cellular telephone in Northern Europe (NMT), and a standard for a mobile reception (base transmission) frequency band is similarly defined. This is defined in consideration of the effect on systems using adjacent bands.

[0006] In order to satisfy this standard, when trying to cope with the conventional wireless relay amplifier, the frequency characteristics of the band are:
9 comprising the duplexer 12 for the base station and the duplexer 15 for the mobile station
This is realized by increasing the attenuation gradient of the 00 MHz band RF-BPF (high frequency bandpass filter).

However, the conventional RF-BPF is a seven-stage BPF using seven 7 mm-square dielectric resonators, and has a pass loss of about 6 dB in a center frequency band of 902.5 MHz. There are several problems in modifying the attenuation characteristics of such a 900 MHz band filter to satisfy the above standards. (1) In order to further steepen the attenuation gradient on both sides of the RF band, it is necessary to increase the Q of the dielectric resonator constituting the BPF, which increases the cost. (2) In addition, the number of stages increases for steepness, so that the passage loss increases. (3) Further, the deviation in the pass band increases.

From the above, in the configuration of the conventional device shown in FIG. 3, when the BPFs of the two duplexers 12 and 15 are modified as required, both the downlink and the uplink are not used in the conventional device configuration. The following new problems arise. (1) Since the passing loss of the downstream and upstream input-side duplexers 12 and 15 increases, the NF (noise figure) viewed from the device input terminal deteriorates. (2) Similarly, the transmission loss of the apparatus decreases because the transmission loss of the downstream and upstream output-side duplexers 15 and 12 increases.

It is an object of the present invention to provide a low noise (low NF) signal even when the attenuation characteristics of the transmission and reception frequency bands are severely restricted.
Another object of the present invention is to provide a wireless relay amplifying device that can ensure high output.

[0010]

A radio relay amplifier according to the present invention relay-amplifies a downlink signal from a radio base station and then feeds it to an antenna for mobile stations, and an uplink signal from a mobile station. In a wireless relay amplifying device having an upstream amplifying unit that feeds a relay-amplified antenna to a base station antenna, each of the down-amplifying unit and the up-amplifying unit includes a low-noise amplifier unit that amplifies a high-frequency reception signal, An intermediate frequency amplifier for converting the output of the low noise amplifier to an intermediate frequency of about 1/10 of the high frequency, selectively amplifying and then converting the output to a high frequency again, and power-amplifying the high frequency output from the intermediate frequency amplifier; And a high-power amplifier section for outputting an output signal. The intermediate frequency amplifier section includes a non-polar bandpass filter for passing a predetermined frequency band, and a high-frequency reduction section for passing a predetermined frequency band. A polar low-pass filter with a steep gradient and a polar high-pass filter with a predetermined frequency band passed and a low-band attenuation gradient steep are connected in cascade, and a specified attenuation standard and loss It is characterized in that it is configured to meet the standard.

[0011]

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, reference numeral 3 denotes a downstream amplifying unit, which includes a low noise amplifier (LNA) unit 31, an intermediate frequency band amplifier (IF-AMP) unit 32, and a high power amplifier (HPA) unit 33.

The low noise amplifier (LNA) section 31 includes a low noise amplifier 34 and an RF-BPF 35. FIG. 2A is an example of the selection characteristics of the RF-BPF of the present invention. This RF-BPF 35 is a 6-stage BPF using six 5 mm-square dielectric resonators, and has a center frequency of 902.5
The pass loss at MHz is about 3 dB. Compared with the conventional RF-BPF, the number of resonators is reduced, the size is reduced, and the loss is reduced.

Intermediate frequency band amplifier (IF-AMP) section 3
Reference numeral 2 denotes a 90 MHz selective amplifying unit, which is a first local oscillation signal (1
st Local) and a mixer 36 for converting a received signal into an IF (90 MHz) band, an intermediate frequency band filter (IF-
BPF) 37, amplifier 38, intermediate frequency low-pass filter (I
F-LPF) 39, intermediate frequency high-pass filter (IF-HP)
F) 40, input the second local oscillation signal (2nd Local) and IF
It comprises a mixer 41 for converting a signal into a 900 MHz RF band.

The IF-AMP unit 32 plays a role of band selection. The IF-BPF 37 is a non-polar bandpass filter having three LC stages. The IF-LPF 39 is a polar low-pass filter with five LC stages. The IF-HPF 40 is a polarized high-pass filter with five LC stages. The reason for combining these three filters is to ensure the attenuation gradient at the attenuation pole and to cover the fall of the attenuation outside the attenuation pole with the band filter while keeping the in-band deviation as small as possible. FIG.
(B) is an example of a comprehensive selection characteristic in which three filters in the IF stage are cascaded. The pass loss at the center frequency (90 MHz) is about 0.6 dB.

The high power amplifier (HPA) unit 33 has an RF-
It is composed of a BPF 42, an HPA 43, and an isolator 44, and is responsible for increasing the output of the device.

Reference numeral 4 denotes an upstream amplifying unit, which comprises a low noise amplifier unit 45, an IF-AMP unit 46, and a high power amplifier unit 47, like the downstream amplifying unit 3. For the sake of simplicity, a description will be given of the downstream amplification unit. The upstream amplifier 4 in FIG.
Therefore, the description is omitted.

A feature of the present invention is that the downstream amplification unit 3 is connected to the LNA 3
1, IF-AMP 32, and HPA 33, and the point that the in-band frequency characteristic deviation is minimized by the IF-AMP unit 32.

The reason for the three divisions is as follows. The IF-AMP 32 is provided to reduce the frequency to be handled to the IF band, thereby facilitating the implementation of a filter having a large attenuation gradient. The pass loss of the IF band filter is LNA3
1 and only the RF band for HPA 33 has less influence on the whole apparatus than that of FIG. Because the device N
F depends heavily on LNA31, and the output is HPA3
Because it depends on 3.

[0019]

By implementing the present invention, a low-noise, high-output wireless relay amplifying apparatus can be realized even when the attenuation gradient of the transmission / reception frequency band selection standard of the wireless relay amplifying apparatus is strictly specified.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating an example of frequency selection characteristics of an RF stage and an IF stage, which are main components of the present invention.

FIG. 3 is a block diagram of a conventional device.

FIG. 4 is a diagram showing an example of an out-of-band attenuation characteristic standard.

[Explanation of symbols]

 Reference Signs List 1 antenna for base station 2, 12 duplexer for base station 3, 13 downlink amplifying unit 4, 14 uplink amplifying unit 5, 15 duplexer for mobile station 6 antenna for mobile station 31, 45 low noise amplifier unit 32, 46 intermediate frequency Band amplifier section 33, 47 High power amplifier section 34 Low noise amplifier (LNA) 35 RF band band filter (RF-BPF) 36 Mixer 37 IF-BPF 38 AMP 39 IF-LPF 40 IF-HPF 41 Mixer 42 RF-BPF 43 HPA 44 isolator

Continued on the front page (72) Inventor Katsumi Tanaka 3-14-20 Higashinakano Nakano-ku Tokyo

Claims (1)

[Claims] 1. A down-amplifying unit that relays and amplifies a downlink signal from a wireless base station and then feeds it to an antenna for a mobile station, and an uplink amplifier that relays and amplifies an uplink signal from a mobile station and feeds it to an antenna for a base station. A low-noise amplifier unit for amplifying a high-frequency reception signal, and the output of the low-noise amplifier unit is reduced to about 1 / An intermediate frequency amplifier section for converting to a low intermediate frequency of 10, selectively amplifying and then converting to a high frequency again, and a high power amplifier section for power amplifying and outputting a high frequency output from the intermediate frequency amplifier section; The frequency amplifier section includes a non-polar band-pass filter that passes a predetermined frequency band, and a polar low-pass filter that passes a predetermined frequency band and has a steep high-band attenuation gradient. And a cascaded polar high-pass filter having a low-frequency attenuation gradient and a steep low-frequency attenuation gradient, and configured to satisfy predetermined attenuation standards and loss standards. Relay amplifier.