JP4843288B2 - AM / FM mixed signal processor - Google Patents

AM / FM mixed signal processor Download PDF

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JP4843288B2
JP4843288B2 JP2005285606A JP2005285606A JP4843288B2 JP 4843288 B2 JP4843288 B2 JP 4843288B2 JP 2005285606 A JP2005285606 A JP 2005285606A JP 2005285606 A JP2005285606 A JP 2005285606A JP 4843288 B2 JP4843288 B2 JP 4843288B2
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嘉彦 西谷
勝行 松原
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Toshiba Corp
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本発明は、地上の送信局からのＡＭ／ＦＭ混合電波を機上にて受信処理し方位情報を取得するＡＭ／ＦＭ混合信号処理装置に関する。   The present invention relates to an AM / FM mixed signal processing apparatus for receiving and processing AM / FM mixed radio waves from a terrestrial transmitting station on-board to acquire azimuth information.

ＶＨＦ帯のＡＭ／ＦＭ混合電波を用い、地上局から航空機に対して磁方位情報を提供する電波誘導施設が知られている。地上局から送信されるＶＨＦ帯のＡＭ／ＦＭ混合電波には、受信地点の方位によって位相の変化する所定周波数の可変位相信号と、全方向で一定の位相を有する所定周波数の基準位相信号とが含まれる。すなわち、一般には３０Ｈｚの可変位相信号と、同じく３０Ｈｚの基準位相信号で周波数変調された副搬送波信号との和により振幅変調されたＶＨＦ帯の信号が送信される。機上ではこれら基準位相信号と可変位相信号の位相差に基づいて自身の磁方位情報を得ている。   There is known a radio wave induction facility that uses a VHF band AM / FM mixed radio wave and provides magnetic direction information from a ground station to an aircraft. The VHF band AM / FM mixed radio wave transmitted from the ground station includes a variable phase signal having a predetermined frequency whose phase changes depending on the direction of the receiving point, and a reference phase signal having a predetermined frequency having a constant phase in all directions. included. That is, generally, a signal in the VHF band that is amplitude-modulated by the sum of a variable phase signal of 30 Hz and a subcarrier signal that is also frequency-modulated with a reference phase signal of 30 Hz is transmitted. On the machine, its magnetic direction information is obtained based on the phase difference between the reference phase signal and the variable phase signal.

地上の送信局からのＡＭ／ＦＭ混合電波を機上にて受信処理し方位情報を取得するＡＭ／ＦＭ混合信号処理装置の一例を図３に示す。この図３に示すＡＭ／ＦＭ混合信号処理装置３０は、受信処理器３１、ＦＦＴ処理器（１）３２、フィルタ３３、ＦＭ検波器３４、ＦＦＴ処理器（２）３５、及び位相差演算器３６から構成されている。受信処理器３１は、地上の送信局からのＡＭ／ＦＭ混合電波を受信処理し、検波済みのデジタル信号を出力する。ＦＦＴ処理器（１）３２は、受信処理器３１からのデジタル信号に対して高速フーリエ変換処理を行ない、振幅変調波としての可変位相信号を抽出する。   FIG. 3 shows an example of an AM / FM mixed signal processing apparatus that receives and processes AM / FM mixed radio waves from a terrestrial transmitting station on the machine and acquires azimuth information. The AM / FM mixed signal processing apparatus 30 shown in FIG. 3 includes a reception processor 31, an FFT processor (1) 32, a filter 33, an FM detector 34, an FFT processor (2) 35, and a phase difference calculator 36. It is composed of The reception processor 31 receives and processes the AM / FM mixed radio wave from the ground transmitting station and outputs a detected digital signal. The FFT processor (1) 32 performs a fast Fourier transform process on the digital signal from the reception processor 31, and extracts a variable phase signal as an amplitude modulated wave.

フィルタ３３は、基準位相信号で周波数変調された副搬送波信号を通過させ、ＦＭ検波器３４は、このフィルタ３３からの信号をＦＭ検波する。ＦＦＴ処理器（２）３５は、ＦＭ検波器３４からの信号に対して高速フーリエ変換処理を行ない、基準位相信号を抽出する。位相差演算器３６は、ＦＦＴ処理器（１）３２で抽出された可変位相信号と、ＦＦＴ処理器（２）３５で抽出された基準位相信号との位相差を算出し方位情報を出力する。   The filter 33 passes the subcarrier signal frequency-modulated with the reference phase signal, and the FM detector 34 performs FM detection on the signal from the filter 33. The FFT processor (2) 35 performs a fast Fourier transform process on the signal from the FM detector 34, and extracts a reference phase signal. The phase difference calculator 36 calculates the phase difference between the variable phase signal extracted by the FFT processor (1) 32 and the reference phase signal extracted by the FFT processor (2) 35, and outputs azimuth information.

上述のように構成された従来のＡＭ／ＦＭ混合信号処理装置３０では、受信されたＡＭ／ＦＭ混合電波は受信処理器３１で受信処理された後、この信号中の可変位相信号がＦＦＴ処理器（１）３２で抽出される。一方、基準位相信号は、フィルタ３３、ＦＭ検波器３４、及びＦＦＴ処理器（２）３５による一連の信号処理によって抽出される。そして、位相差演算器３６においてこれら可変位相信号と基準位相信号との位相差が算出される。算出結果は、方位情報として後段の機器に送出される。   In the conventional AM / FM mixed signal processing apparatus 30 configured as described above, the received AM / FM mixed radio wave is received and processed by the reception processor 31, and then the variable phase signal in this signal is converted into the FFT processor. (1) Extracted at 32. On the other hand, the reference phase signal is extracted by a series of signal processing by the filter 33, the FM detector 34, and the FFT processor (2) 35. Then, the phase difference calculator 36 calculates the phase difference between the variable phase signal and the reference phase signal. The calculation result is sent to the subsequent device as direction information.

なお、上述した従来のＡＭ／ＦＭ混合信号処理装置は、例えば、下記の特許文献１に開示されている。
特開２００１−３４３４４０号公報（第７ページ、図４） The above-described conventional AM / FM mixed signal processing apparatus is disclosed in, for example, Patent Document 1 below.
JP 2001-343440 A (7th page, FIG. 4)

ところで、フーリエ級数展開では、解析対象の信号を基本周波数とその高次周波数の信号からなる無限級数に展開することによって、時間領域から周波数領域に写像する。上述したＦＦＴ処理器（１）３２、及びＦＦＴ処理器（２）３５でのＦＦＴ処理においても、受信処理器３１から送出される時間領域の信号を周波数領域に写像する。   By the way, in Fourier series expansion, the signal to be analyzed is mapped to the frequency domain from the time domain by expanding the signal to be analyzed into an infinite series consisting of a fundamental frequency and a signal of the higher order frequency. Also in the FFT processing in the FFT processor (1) 32 and the FFT processor (2) 35 described above, the time domain signal sent from the reception processor 31 is mapped to the frequency domain.

しかしながら、受信処理器３１から送出されるデジタル信号は、所定の周期でサンプリングされた信号であり、解析される周波数もサンプリング周波数を基準とした有限の高次周波数の範囲となる上、これら解析される周波数の集まりのみで構成されていない。このため、これらのＦＦＴ処理器（１）３２、及びＦＦＴ処理器（２）３５から抽出された可変位相信号及び基準位相信号には、それぞれにＦＦＴ処理による誤差が含まれることになり、この後に位相差演算器３６において算出されたこれら２信号間の位相差にも誤差を生じ、方位情報の精度を劣化させていた。   However, the digital signal transmitted from the reception processor 31 is a signal sampled at a predetermined cycle, and the analyzed frequency is in a finite high-order frequency range based on the sampling frequency, and these are analyzed. It is not composed of only a collection of frequencies. For this reason, each of the variable phase signal and the reference phase signal extracted from the FFT processor (1) 32 and the FFT processor (2) 35 includes an error due to the FFT processing. An error also occurs in the phase difference between these two signals calculated by the phase difference calculator 36, degrading the accuracy of the azimuth information.

また、例えば自身の移動等によって電波受信環境が頻繁に変化する中にあっては、受信信号にマルチパスによる外乱が発生する。このような外乱を受けた場合には、受信されたＡＭ／ＦＭ混合電波に対してマルチパスによる不規則な振幅変調が加わって不要な周波数成分が生じ、ＦＦＴ処理及びその後の位相差演算時における誤差となって方位情報の精度を劣化させていた。   In addition, for example, when the radio wave reception environment frequently changes due to its own movement or the like, disturbance due to multipath occurs in the received signal. When such disturbances are received, irregular amplitude modulation due to multipath is added to the received AM / FM mixed radio wave, and unnecessary frequency components are generated. During FFT processing and subsequent phase difference calculation, It became an error and deteriorated the accuracy of the direction information.

さらに、上述したＦＦＴ処理やフィルタ処理等の信号処理では、大量のデータ処理を伴う演算を繰りかえし実行する。このため、高速演算が可能な専用のプロセッサを用いても処理時間を短縮することが困難であり、演算負荷を軽減することによって高速化することが望まれていた。   Further, in the above-described signal processing such as FFT processing and filter processing, operations involving a large amount of data processing are repeated. For this reason, it is difficult to shorten the processing time even if a dedicated processor capable of high-speed computation is used, and it has been desired to increase the speed by reducing the computation load.

本発明は、上述の事情を考慮してなされたものであり、地上の送信局からのＡＭ／ＦＭ混合電波を受信して信号処理する際に、演算誤差要因を減らして良好な精度の方位情報を得るとともに、処理速度を向上させたＡＭ／ＦＭ混合信号処理装置を提供することを目的とする。   The present invention has been made in consideration of the above-described circumstances. When receiving and processing an AM / FM mixed radio wave from a terrestrial transmission station, the azimuth information with good accuracy can be obtained by reducing the calculation error factor. The object of the present invention is to provide an AM / FM mixed signal processing apparatus with improved processing speed.

上記目的を達成するために、本発明のＡＭ／ＦＭ混合信号処理装置は、所定周波数の可変位相信号とこの信号と同じ周波数の基準位相信号で周波数変調された副搬送波との和により振幅変調された送信波を受信処理し、前記可変位相信号と前記基準位相信号との位相差に基づいて方位情報を取得するＡＭ／ＦＭ混合信号処理装置であって、前記送信波を受信処理し検波済みのデジタル信号を出力する受信処理器と、この検波済みのデジタル信号の中から前記所定周波数の可変位相信号の周波数成分を通過させる第１の狭帯域デジタルフィルタと、この第１の狭帯域デジタルフィルタを通過したデジタル信号に対して高速フーリエ変換処理を施し位相情報を含む前記可変位相信号を抽出する第１のＦＦＴ処理器と、前記検波済みのデジタル信号の中から前記基準位相信号で周波数変調された副搬送波の周波数帯域を通過させるフィルタリング処理とともに通過後のデジタル信号に対しヒルベルト変換処理を行ない出力するＦＭフィルタドヒルベルト変換器と、このＦＭフィルタドヒルベルト変換器から出力されるデジタル信号を微分して出力する微分器と、このデジタル微分器から出力されるデジタル信号の中から前記所定周波数の基準位相信号の周波数成分を通過させる第２の狭帯域デジタルフィルタと、この第２の狭帯域デジタルフィルタを通過したデジタル信号に対して高速フーリエ変換処理を施し位相情報を含む前記基準位相信号を抽出する第２のＦＦＴ処理器と、前記第1のＦＦＴ処理器により抽出された前記位相情報を含む可変位相信号と前記第２のＦＦＴ処理器により抽出された前記位相情報を含む基準位相信号との位相差に基づいて方位情報を算出する位相差演算器とを有することを特徴とする。 In order to achieve the above object, the AM / FM mixed signal processing apparatus of the present invention is amplitude-modulated by the sum of a variable phase signal having a predetermined frequency and a subcarrier frequency-modulated with a reference phase signal having the same frequency as this signal. An AM / FM mixed signal processing apparatus that receives received transmission waves and obtains azimuth information based on a phase difference between the variable phase signal and the reference phase signal. A reception processor that outputs a digital signal, a first narrowband digital filter that passes the frequency component of the variable phase signal of the predetermined frequency from the detected digital signal, and the first narrowband digital filter. A first FFT processor that performs fast Fourier transform processing on the digital signal that has passed and extracts the variable phase signal including phase information; and the detected digital signal And FM filter de Hilbert transformer for outputting performs a Hilbert transform processing on the digital signal after passing through with the filtering process to pass the frequency band of sub-carriers that are frequency modulated by the reference phase signal from within, the FM filter de Hilbert transform A differentiator that differentiates and outputs a digital signal output from the generator, and a second narrowband digital filter that passes the frequency component of the reference phase signal of the predetermined frequency from the digital signal output from the digital differentiator A second FFT processor for performing a fast Fourier transform on the digital signal that has passed through the second narrowband digital filter and extracting the reference phase signal including phase information; and the first FFT processor Extracted by the variable phase signal including the phase information extracted by the second FFT processor. And having a phase difference calculator for calculating the azimuth information on the basis of the phase difference between the reference phase signal including the phase information.

本発明によれば、地上の送信局からのＡＭ／ＦＭ混合電波を受信して信号処理する際に、演算誤差要因を減らして良好な精度を有する方位情報を得るとともに、処理速度を向上させたＡＭ／ＦＭ混合信号処理装置を得ることができる。   According to the present invention, when AM / FM mixed radio waves from a terrestrial transmitting station are received and processed, the calculation error factor is reduced to obtain azimuth information having good accuracy, and the processing speed is improved. An AM / FM mixed signal processing apparatus can be obtained.

以下に、本発明に係るＡＭ／ＦＭ混合信号処理装置を実施するための最良の形態について、図１及び図２を参照して説明する。   The best mode for carrying out the AM / FM mixed signal processing apparatus according to the present invention will be described below with reference to FIG. 1 and FIG.

図１は、本発明に係るＡＭ／ＦＭ混合信号処理装置の一実施例を示すブロック図である。この図１に例示したＡＭ／ＦＭ混合信号処理装置１は、受信処理器１１、第１の狭帯域フィルタとしての狭帯域デジタルフィルタ（１）１２、第１のＦＦＴ処理器としてのＦＦＴ処理器（１）１３、ＦＭフィルタドヒルベルト変換器１４、デジタル微分器１５、第２の狭帯域フィルタとしての狭帯域デジタルフィルタ（２）１６、第２のＦＦＴ処理器としてのＦＦＴ処理器（２）１７、及び位相差演算器１８から構成されている。   FIG. 1 is a block diagram showing an embodiment of an AM / FM mixed signal processing apparatus according to the present invention. The AM / FM mixed signal processing apparatus 1 illustrated in FIG. 1 includes a reception processor 11, a narrowband digital filter (1) 12 as a first narrowband filter, and an FFT processor ( 1) 13, FM filtered Hilbert transformer 14, digital differentiator 15, narrowband digital filter (2) 16 as a second narrowband filter, FFT processor (2) 17 as a second FFT processor, And a phase difference calculator 18.

受信処理器１１は、地上の送信局からのＡＭ／ＦＭ混合電波を受信処理して検波済みのデジタル信号を出力する。狭帯域デジタルフィルタ（１）１２は、受信処理器１１からのデジタル信号中から可変位相信号の周波数成分を通過させる狭帯域のバンドパスフィルタであり、その構成の一例を図２に示す。本実施例においては、図２に例示したように、このデジタルフィルタは、ＩＩＲ（Ｉｎｆｉｎｉｔｅ Ｉｍｐｕｌｓｅ Ｒｅｓｐｏｎｓｅ）型として構成されており、より低次で良好な狭帯域特性を得るとともに、タップ数を減らすことができるので、演算負荷を軽減して高速処理を可能にしている。ＦＦＴ処理器（１）１３は、狭帯域デジタルフィルタ（１）１２を通過したデジタル信号に対して高速フーリエ変換処理を行ない、位相情報を含む可変位相信号を抽出する。   The reception processor 11 receives AM / FM mixed radio waves from a terrestrial transmission station and outputs a detected digital signal. The narrowband digital filter (1) 12 is a narrowband bandpass filter that passes the frequency component of the variable phase signal from the digital signal from the reception processor 11, and an example of the configuration is shown in FIG. In this embodiment, as illustrated in FIG. 2, this digital filter is configured as an IIR (Infinite Impulse Response) type to obtain a lower-order and good narrowband characteristic and to reduce the number of taps. Therefore, the calculation load is reduced and high-speed processing is possible. The FFT processor (1) 13 performs a fast Fourier transform process on the digital signal that has passed through the narrowband digital filter (1) 12, and extracts a variable phase signal including phase information.

ＦＭフィルタドヒルベルト変換器１４は、受信処理器１１からのデジタル信号中から、基準位相信号によって周波数変調された副搬送波の周波数帯域を通過させるとともに、ヒルベルト変換処理を行なう。本実施例においては、入力されるデジタル信号を高速フーリエ変換し、そのマイナスの周波数成分をゼロにするとともに、プラスの周波数成分のうち、通過させるべき周波数変調された副搬送波の周波数帯域以外もゼロにした後に逆高速フーリエ変換を行なうことにより実現している。すなわち、副搬送波のフィルタリングとヒルベルト変換とを同時に行なうことによって高速処理を可能にしている。   The FM filtered Hilbert transformer 14 passes the frequency band of the subcarrier frequency-modulated by the reference phase signal from the digital signal from the reception processor 11 and performs the Hilbert transform process. In this embodiment, the input digital signal is fast Fourier transformed to make its negative frequency component zero, and the positive frequency component other than the frequency-modulated subcarrier frequency band to be passed is zero. This is realized by performing inverse fast Fourier transform after the above. That is, high-speed processing is enabled by simultaneously performing subcarrier filtering and Hilbert transform.

デジタル微分器１５は、ＦＭフィルタドヒルベルト変換器１４の処理結果に対してデジタル微分を行なう。本実施例においては、下記の式（１）によりデジタル微分を実現している。

Figure 0004843288
The digital differentiator 15 performs digital differentiation on the processing result of the FM filtered Hilbert transformer 14. In this embodiment, digital differentiation is realized by the following equation (1).
Figure 0004843288

また、ＦＭフィルタドヒルベルト変換器１４とこのデジタル微分器１５とで、周波数変調された副搬送波をＦＭ検波している。   The FM filtered Hilbert converter 14 and the digital differentiator 15 perform FM detection on the frequency-modulated subcarrier.

狭帯域デジタルフィルタ（２）１６は、ＦＭ検波されたデジタル微分器１５からのデジタル信号中から基準位相信号の周波数成分を通過させる狭帯域のバンドパスフィルタである。本実施例においては、この狭帯域デジタルフィルタ（２）１６は、図２に例示した狭帯域デジタルフィルタ（１）１２と同様にＩＩＲ型で構成されており、良好な狭帯域特性と演算負荷を軽減した高速なフィルタ処理を実現している。   The narrowband digital filter (2) 16 is a narrowband bandpass filter that passes the frequency component of the reference phase signal from the digital signal from the digital differentiator 15 subjected to FM detection. In the present embodiment, the narrow band digital filter (2) 16 is formed of an IIR type similarly to the narrow band digital filter (1) 12 illustrated in FIG. 2, and has a good narrow band characteristic and a calculation load. Reduced high-speed filter processing is realized.

ＦＦＴ処理器（２）１７は、狭帯域デジタルフィルタ（２）１６を通過したデジタル信号に対して高速フーリエ変換処理を行ない、位相情報を含む基準位相信号を抽出する。位相差演算器１８は、ＦＦＴ処理器（１）１３で抽出された可変位相信号と、ＦＦＴ処理器（２）１７で抽出された基準位相信号との位相差に基づいて方位情報を算出し出力する。   The FFT processor (2) 17 performs a fast Fourier transform process on the digital signal that has passed through the narrowband digital filter (2) 16, and extracts a reference phase signal including phase information. The phase difference calculator 18 calculates and outputs azimuth information based on the phase difference between the variable phase signal extracted by the FFT processor (1) 13 and the reference phase signal extracted by the FFT processor (2) 17. To do.

次に、前述の図１を参照して、上述のように構成された本発明に係るＡＭ／ＦＭ混合信号処理装置１の動作を説明する。まず地上の送信局からのＡＭ／ＦＭ混合電波が受信処理器１１で受信される。地上の送信局からのＡＭ／ＦＭ混合電波は、下記の式（２）のように表される。

Figure 0004843288
Next, the operation of the AM / FM mixed signal processing apparatus 1 according to the present invention configured as described above will be described with reference to FIG. First, the AM / FM mixed radio wave from the ground transmitting station is received by the reception processor 11. The AM / FM mixed radio wave from the terrestrial transmitting station is expressed by the following equation (2).
Figure 0004843288

ここに、電波誘導施設においては、変調周波数ｆ１は３０Ｈｚ、また副搬送波周波数ｆ２は９９６０Ｈｚである。すなわち、地上の送信局からのＡＭ／ＦＭ混合電波は、可変位相信号としての３０Ｈｚの変調波と、同じく３０Ｈｚの基準位相信号としての変調波で周波数変調された９９６０Ｈｚの副搬送波との和により振幅変調されている。   Here, in the radio wave induction facility, the modulation frequency f1 is 30 Hz, and the subcarrier frequency f2 is 9960 Hz. That is, the AM / FM mixed radio wave from the terrestrial transmitting station has an amplitude by the sum of a 30 Hz modulated wave as a variable phase signal and a 9960 Hz subcarrier that is also frequency-modulated with a modulated wave as a 30 Hz reference phase signal. It is modulated.

受信されたＡＭ／ＦＭ混合電波は、受信処理器１１にて増幅、周波数変換、フィルタリング等の受信処理が施された後に包絡線検波される。検波後に得られる信号の電圧式は下記の式（３）のように表される。

Figure 0004843288
The received AM / FM mixed radio wave is subjected to reception processing such as amplification, frequency conversion, filtering and the like by the reception processor 11 and then subjected to envelope detection. The voltage equation of the signal obtained after detection is expressed as the following equation (3).
Figure 0004843288

すなわち、この検波後の信号には、周波数ｆ１（３０Ｈｚに相当）の可変位相信号の成分と、同じく周波数ｆ１（３０Ｈｚに相当）の基準位相信号で周波数変調された周波数ｆ２（９９６０Ｈｚに相当）の副搬送波の成分とが含まれる。この信号はさらにＡＤ変換され、検波済みのデジタル信号として狭帯域デジタルフィルタ（１）１２、及びＦＭフィルタドヒルベルト変換器１４へ、それぞれ送出される。ここに、狭帯域デジタルフィルタ（１）１２は、可変位相信号の抽出処理を実行する系統の初段であり、またＦＭフィルタドヒルベルト変換器１４は、基準位相信号の抽出処理を実行する系統の初段である。以下に、それぞれの系統毎に動作を説明する。   That is, the detected signal has a variable phase signal component having a frequency f1 (corresponding to 30 Hz) and a frequency f2 (corresponding to 9960 Hz) frequency-modulated with a reference phase signal having the same frequency f1 (corresponding to 30 Hz). Subcarrier component. This signal is further AD-converted and sent as a detected digital signal to the narrowband digital filter (1) 12 and the FM filtered Hilbert converter 14, respectively. Here, the narrowband digital filter (1) 12 is the first stage of the system that executes the extraction process of the variable phase signal, and the FM filtered Hilbert converter 14 is the first stage of the system that executes the extraction process of the reference phase signal. It is. The operation will be described below for each system.

可変位相信号の抽出処理を実行する系統では、受信処理器１１からのデジタル信号は、まず狭帯域デジタルフィルタ（１）１２によって受けとられる。狭帯域デジタルフィルタ（１）１２は、可変位相信号の周波数を中心周波数とする狭帯域のフィルタである。このフィルタによって、受信処理器１１からのデジタル信号中から、可変位相信号の周波数以外の不要な周波数成分を大幅に減衰させている。フィルタ通過後のデジタル信号は、ＦＦＴ処理器（１）１３に送出される。   In a system that performs variable phase signal extraction processing, the digital signal from the reception processor 11 is first received by the narrowband digital filter (1) 12. The narrowband digital filter (1) 12 is a narrowband filter whose center frequency is the frequency of the variable phase signal. By this filter, unnecessary frequency components other than the frequency of the variable phase signal are greatly attenuated in the digital signal from the reception processor 11. The digital signal after passing through the filter is sent to the FFT processor (1) 13.

ＦＦＴ処理器（１）１３では、このフィルタ後のデジタル信号を受けとってＦＦＴ処理を施し、位相情報を含む可変位相信号を抽出する。このときに不要な周波数成分は大幅に減衰しているので、ＦＦＴ処理における演算誤差要因を減らして良好な抽出結果を得ている。抽出された可変位相信号は、位相情報を含めて位相差演算器１８に送出される。   The FFT processor (1) 13 receives the filtered digital signal and performs an FFT process to extract a variable phase signal including phase information. At this time, unnecessary frequency components are greatly attenuated, so that a good extraction result is obtained by reducing the calculation error factor in the FFT processing. The extracted variable phase signal is sent to the phase difference calculator 18 including the phase information.

一方、基準位相信号の抽出処理を実行する系統では、受信処理器１１からのデジタル信号は、まずＦＭフィルタドヒルベルト変換器１４によって受けとられる。このＦＭフィルタドヒルベルト変換器１４では、受信処理器からのデジタル信号の中から、基準位相信号によって周波数変調された副搬送波の周波数帯域を通過させると同時に、ヒルベルト変換処理を行なう。これら処理後の信号は、さらにデジタル微分器１５により微分され、副搬送波がＦＭ検波される。   On the other hand, in the system that executes the extraction process of the reference phase signal, the digital signal from the reception processor 11 is first received by the FM filtered Hilbert converter 14. The FM filtered Hilbert transformer 14 passes the frequency band of the subcarrier frequency-modulated by the reference phase signal from the digital signal from the reception processor and simultaneously performs the Hilbert transform process. These processed signals are further differentiated by the digital differentiator 15, and the subcarrier is FM-detected.

この検波後の信号には、３０Ｈｚの基準位相信号の成分が含まれているので、さらにこの信号は、基準位相信号の周波数を中心とする狭帯域デジタルフィルタ（２）１６を通過して不要な周波数成分が除去された上で、ＦＦＴ処理器（２）に送出される。ＦＦＴ処理器（２）１７では、このフィルタ後のデジタル信号を受けとってＦＦＴ処理を施し、位相情報を含む基準位相信号を抽出する。このときのＦＦＴ処理においては、不要な周波数成分が除去されているので、演算誤差要因を減らして良好な抽出結果を得ている。抽出された基準位相信号は、位相情報を含めて位相差演算器１８に送出される。   Since the signal after the detection includes a component of the reference phase signal of 30 Hz, this signal is unnecessary after passing through the narrowband digital filter (2) 16 centering on the frequency of the reference phase signal. After the frequency component is removed, it is sent to the FFT processor (2). The FFT processor (2) 17 receives the filtered digital signal, performs FFT processing, and extracts a reference phase signal including phase information. In the FFT processing at this time, since unnecessary frequency components are removed, a good extraction result is obtained by reducing the calculation error factor. The extracted reference phase signal is sent to the phase difference calculator 18 including the phase information.

位相差演算器１８では、ＦＦＴ処理器（１）１３で抽出された可変位相信号と、ＦＦＴ処理器（２）１７で抽出された基準位相信号との位相差を算出し、方位情報を取得する。この位相差の算出は、次のような演算により行なう。すなわち、ＦＦＴ処理器（１）１３で抽出された可変位相信号、及びＦＦＴ処理器（２）１７で抽出された基準位相信号は、それぞれ複素数として下記の式（４）、及び式（５）で表される。

Figure 0004843288

Figure 0004843288
 The phase difference calculator 18 calculates the phase difference between the variable phase signal extracted by the FFT processor (1) 13 and the reference phase signal extracted by the FFT processor (2) 17, and acquires azimuth information. . This phase difference is calculated by the following calculation. That is, the variable phase signal extracted by the FFT processor (1) 13 and the reference phase signal extracted by the FFT processor (2) 17 are respectively expressed as complex numbers by the following equations (4) and (5). expressed.
Figure 0004843288
Figure 0004843288


ここで、下記の式（６）の角度計算式に基づいて角度差を複素演算する。

Figure 0004843288

Here, the angle difference is complex-calculated based on the angle calculation formula of the following formula (6).
Figure 0004843288

さらに、この式（６）で得られた複素値の実数部及び虚数部を用い、下記の式（７）の演算によって方位情報θを取得する。

Figure 0004843288
Furthermore, using the real part and the imaginary part of the complex value obtained by the equation (6), the azimuth information θ is obtained by the calculation of the following equation (7).
Figure 0004843288

そして、取得された方位情報は後段の機器に送出される。   Then, the acquired azimuth information is sent to the subsequent device.

以上説明したように、本実施例においては、受信したＡＭ／ＦＭ混合電波から位相情報を含む可変位相信号及び基準位相信号を抽出する際に、これらの信号周波数を中心周波数とする狭帯域デジタルフィルタ（１）１２、及び狭帯域デジタルフィルタ（２）１６を設け、受信処理されたデジタル信号中からこれらフィルタによって不要な周波数成分を大幅に減衰させた後にＦＦＴ処理を施している。これにより、マルチパス等の外乱要因を含むＦＦＴ演算処理における演算誤差の要因を減らすことができ、演算誤差の少ない可変位相信号及び基準位相信号に基づいて良好な精度を有する方位情報を得ることができる。   As described above, in this embodiment, when a variable phase signal including phase information and a reference phase signal are extracted from a received AM / FM mixed radio wave, a narrowband digital filter having these signal frequencies as a center frequency is extracted. (1) 12 and narrowband digital filter (2) 16 are provided, and FFT processing is performed after unnecessary frequency components are greatly attenuated by these filters in the received digital signal. As a result, it is possible to reduce the cause of calculation error in FFT calculation processing including disturbance factors such as multipath, and to obtain azimuth information having good accuracy based on the variable phase signal and the reference phase signal with less calculation error. it can.

また、上記した狭帯域デジタルフィルタ（１）１２、及び狭帯域デジタルフィルタ（２）１６をいずれもＩＩＲ型の構成とし、より少ないタップ数で良好な狭帯域特性を得ている。加えて、基準位相信号の抽出処理を実行する系統では、ＦＭフィルタドヒルベルト変換器１４により、副搬送波のフィルタリングとヒルベルト変換とを同時に実現している。これらにより、演算の処理負荷を軽減して処理速度を向上させることができる。   In addition, both the narrowband digital filter (1) 12 and the narrowband digital filter (2) 16 described above have an IIR configuration, and good narrowband characteristics are obtained with a smaller number of taps. In addition, in the system that executes the extraction process of the reference phase signal, the FM filtered Hilbert transformer 14 simultaneously realizes subcarrier filtering and Hilbert transform. As a result, the processing load of computation can be reduced and the processing speed can be improved.

本発明に係るＡＭ／ＦＭ混合信号処理装置の一実施例を示すブロック図。The block diagram which shows one Example of the AM / FM mixed signal processing apparatus which concerns on this invention. 狭帯域デジタルフィルタの構成の一例を示すブロック図。The block diagram which shows an example of a structure of a narrow-band digital filter. 従来のＡＭ／ＦＭ混合信号処理装置の一例を示すブロック図。The block diagram which shows an example of the conventional AM / FM mixed signal processing apparatus.

符号の説明Explanation of symbols

１ ＡＭ／ＦＭ混合信号処理装置
１１ 受信処理器
１２ 狭帯域デジタルフィルタ（１）
１３ ＦＦＴ処理器（１）
１４ ＦＭフィルタドヒルベルト変換器
１５ デジタル微分器
１６ 狭帯域デジタルフィルタ（２）
１７ ＦＦＴ処理器（２）
１８ 位相差演算器 DESCRIPTION OF SYMBOLS 1 AM / FM mixed signal processing apparatus 11 Reception processor 12 Narrow band digital filter (1)
13 FFT processor (1)
14 FM filtered Hilbert converter 15 Digital differentiator 16 Narrowband digital filter (2)
17 FFT processor (2)
18 Phase difference calculator

Claims (1)

所定周波数の可変位相信号とこの信号と同じ周波数の基準位相信号で周波数変調された副搬送波との和により振幅変調された送信波を受信処理し、前記可変位相信号と前記基準位相信号との位相差に基づいて方位情報を取得するＡＭ／ＦＭ混合信号処理装置であって、
前記送信波を受信処理し検波済みのデジタル信号を出力する受信処理器と、
この検波済みのデジタル信号の中から前記所定周波数の可変位相信号の周波数成分を通過させる第１の狭帯域デジタルフィルタと、
この第１の狭帯域デジタルフィルタを通過したデジタル信号に対して高速フーリエ変換処理を施し位相情報を含む前記可変位相信号を抽出する第１のＦＦＴ処理器と、
前記検波済みのデジタル信号の中から前記基準位相信号で周波数変調された副搬送波の周波数帯域を通過させるフィルタリング処理とともに通過後のデジタル信号に対しヒルベルト変換処理を行ない出力するＦＭフィルタドヒルベルト変換器と、
このＦＭフィルタドヒルベルト変換器から出力されるデジタル信号を微分して出力する微分器と、
このデジタル微分器から出力されるデジタル信号の中から前記所定周波数の基準位相信号の周波数成分を通過させる第２の狭帯域デジタルフィルタと、
この第２の狭帯域デジタルフィルタを通過したデジタル信号に対して高速フーリエ変換処理を施し位相情報を含む前記基準位相信号を抽出する第２のＦＦＴ処理器と、
前記第1のＦＦＴ処理器により抽出された前記位相情報を含む可変位相信号と前記第２のＦＦＴ処理器により抽出された前記位相情報を含む基準位相信号との位相差に基づいて方位情報を算出する位相差演算器と
を有することを特徴とするＡＭ／ＦＭ混合信号処理装置。 A transmission wave amplitude-modulated by the sum of a variable phase signal of a predetermined frequency and a subcarrier frequency-modulated with a reference phase signal of the same frequency as this signal is received and processed, and the level of the variable phase signal and the reference phase signal is An AM / FM mixed signal processing apparatus that acquires azimuth information based on a phase difference,
A reception processor for receiving the transmission wave and outputting a detected digital signal;
A first narrowband digital filter that passes the frequency component of the variable phase signal of the predetermined frequency from the detected digital signal;
A first FFT processor that performs a fast Fourier transform on the digital signal that has passed through the first narrowband digital filter and extracts the variable phase signal including phase information;
An FM filtered Hilbert transformer that performs a Hilbert transform process on the digital signal after passing through a filtering process that passes the frequency band of the subcarrier frequency-modulated with the reference phase signal from the detected digital signal; ,
A differentiator that differentiates and outputs a digital signal output from the FM filtered Hilbert transformer;
A second narrowband digital filter that passes a frequency component of the reference phase signal of the predetermined frequency from the digital signal output from the digital differentiator;
A second FFT processor that performs a fast Fourier transform on the digital signal that has passed through the second narrowband digital filter and extracts the reference phase signal including phase information;
Direction information is calculated based on a phase difference between the variable phase signal including the phase information extracted by the first FFT processor and the reference phase signal including the phase information extracted by the second FFT processor. And an AM / FM mixed signal processing apparatus.
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CN104677580A (en) * 2015-01-30 2015-06-03 燕山大学 Rotary mechanical fault diagnosis method based on analytical modal decomposition
CN106441894A (en) * 2016-09-28 2017-02-22 清华大学 Magnetic suspension bearing shaft system falling track response recognition method and device based on Hilbert transform
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