JP2004201066A - Receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a receiver capable of obtaining accurate reception signal data even when received signal fluctuates fast outside the range and even when the received signal includes modulation of an amplitude component. <P>SOLUTION: Respective systems for reception signal processing hold amplifiers 11, 21, AGC (automatic gain control) circuits 12 and 22 for performing automatic gain control with mutually different response speeds and AD converters 13 and 23, respectively, and a digital signal processor 30 which receives signals that pass through the systems selects digital data with the lowest error rate between the systems. Then, the reception signal data which has the lowest error rate can be obtained. For example, when the received signal is disturbed by fast level fluctuations such as fading, the output of a system comprising an AGC circuit with a fast response speed is selected, and when the received signal takes a modulation system with an amplitude component, it is enough that the output of a system comprising an AGC circuit with a slow response speed is selected. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a receiving apparatus, and more particularly, to a receiving apparatus using an AGC circuit so as to be as little affected by fading or the like.
[0002]
[Prior art]
In the conventional receiving apparatus, an AGC circuit is arranged in a part of an analog input circuit. However, the characteristic (response speed) of the AGC circuit is fixed, and the function of the AGC characteristic is switched according to the situation. I haven't. Therefore, an accurate receiving operation can be performed when the state of the input signal is within a normal range expected in design, but an accurate receiving operation cannot be performed when the state exceeds the set range. That is, when the response speed of the AGC circuit is set to be slow, a received signal including a fast level fluctuation such as fading cannot follow the fluctuation speed and causes many errors in the received signal data. Conversely, when the response speed of the AGC circuit is set to be fast, or when a received signal of a modulation method in which the received signal includes the modulation of the amplitude component is received, the AGC circuit tries to keep the signal level constant. In order to operate, even if an error is generated in the amplitude component and the received signal is received at a normal level, many errors are generated in the received signal data (for example, the level of the unique word area is different from the level of the data area). Case).
[0003]
[Problems to be solved by the invention]
In the above-described conventional receiving apparatus, since the characteristics of the AGC circuit are fixedly set, when the received signal fluctuates quickly outside the range or when the received signal includes amplitude component modulation, In either case, there is a problem that accurate received signal data cannot be obtained.
[0004]
The present invention has been made in order to solve the above-described problem, and it is possible to accurately receive a received signal even when the received signal fluctuates rapidly and the amplitude of the received signal is modulated. It is an object of the present invention to provide a receiving device capable of obtaining signal data.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problem, the present invention provides a plurality of amplifier circuits for amplifying received signals, a plurality of AGC circuits for performing automatic gain control with different response speeds on the outputs of the respective amplifier circuits, and a plurality of AGC circuits. A plurality of A / D converters for respectively A / D converting the outputs; and a digital signal processing device for calculating the error rate of the received signal data at the output of each A / D converter and selecting and outputting the output of the A / D converter having the lowest error rate. .
[0006]
According to such a configuration, each system for signal processing has an AGC circuit that performs automatic gain control with different response speeds, and the digital signal processing device has the highest error rate among these systems. , Digital data with a low error rate can be selected, and as a result, received signal data with the lowest error rate can be obtained. For example, when the received signal is disturbed by a fast level fluctuation such as fading, an output of a system having an AGC circuit having a fast response speed is selected. What is necessary is just to select the output of the system provided with the AGC circuit whose response speed is slow.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing an embodiment of the receiving apparatus of the present invention. An analog reception signal S0 from an antenna (not shown) or the like is processed separately in two systems. In the first system, the received signal S0 is amplified by the amplifier 11, delivered to the AGC circuit 12 as a signal S11, and subjected to automatic gain control. The signal S12 output from the AGC circuit 12 that has been subjected to the automatic gain control is transferred to the AD converter 13. In the second system, the received signal S0 is amplified by the amplifier 21, delivered to the AGC circuit 22 as the signal S21, and subjected to automatic gain control. The signal S22 output from the AGC circuit 22 that has been subjected to the automatic gain control is transferred to the AD converter 23. In this case, the response speed of the AGC circuit 12 is set to be fast, and the response speed of the AGC circuit 12 is set to be slow. The AGC circuit 12 performs automatic gain control on the signals S1 and S2 in accordance with the respective AGC characteristics.
[0008]
The A / D converters 13 and 23 receive the signals S12 and S22 to which the automatic gain control has been applied by the AGC circuits 12 and 22, AD convert the received signals, and output them as digital data S13 and S23. The digital signal processor (DSP) 30 calculates an error rate of each of the digital data S13 and S23 based on the digital data S13 and S23 from the AD converters 13 and 23, and calculates an error rate among the first and second systems. The digital data with the lower rate is output to the succeeding stage as the selected reception signal digital data S30. Note that the waveform display of FIG. 1 shows a change in the received signal when the level is set to be different between the unique word part and the data part in the modulation method with the equalization function.
[0009]
Therefore, when the received signal S0 is disturbed by a fast fluctuation such as fading, the signal that has passed through the amplifier 11, the AGC circuit 12, and the AD converter 13 of the first system is transmitted to the subsequent stage as the selected received signal digital data S30. When the received signal S0 has a modulation method having an amplitude component, the signal having passed through the second-system amplifier 21, AGC circuit 22, and AD converter 23 is output to the subsequent stage as selected reception signal digital data S30. Therefore, it is possible to select an AGC characteristic suitable for the present situation, and to output accurate received signal data to the subsequent stage as selected received signal digital data S30. In the above example, two systems are used for signal processing. However, three or more systems may be used, and digital data of the system having the lowest error rate among these multiple systems is selected reception signal digital data. What is necessary is just to output it to the succeeding stage as S30.
[0010]
【The invention's effect】
Since the receiving device of the present invention is configured as described above,
In each system for signal processing including an amplifier circuit, an AGC circuit, and an AD converter, each AGC circuit performs automatic gain control with a different response speed. Therefore, the digital signal processing device can obtain the received signal data with the lowest error rate by selecting the digital data with the lowest error rate from these systems. For example, when the received signal is disturbed by a fast level fluctuation such as fading, an output of a system having an AGC circuit having a fast response speed is selected, and when the received signal employs a modulation method having an amplitude component, An output of a system including an AGC circuit having a low response speed is selected.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating an embodiment of a receiving device of the present invention.
[Explanation of symbols]
11, 21 Amplifier 12, 22 AGC circuit 13, 23 AD converter 30 Digital signal processor (DSP)

Claims (1)

A plurality of amplifier circuits for respectively amplifying the received signal,
A plurality of AGC circuits that perform automatic gain control with different response speeds on the output of each amplifier circuit;
A plurality of AD converters for A / D converting the output of each AGC circuit,
A digital signal processing device that calculates an error rate of received signal data at an output of each AD converter and selects and outputs an output of the AD converter with the lowest error rate.

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