JPS60174505A - Frequency converter - Google Patents
Frequency converterInfo
- Publication number
- JPS60174505A JPS60174505A JP3124284A JP3124284A JPS60174505A JP S60174505 A JPS60174505 A JP S60174505A JP 3124284 A JP3124284 A JP 3124284A JP 3124284 A JP3124284 A JP 3124284A JP S60174505 A JPS60174505 A JP S60174505A
- Authority
- JP
- Japan
- Prior art keywords
- pass filter
- frequency
- low
- signal
- output
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
- H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Transmitters (AREA)
Abstract
Description
〔発明の属する技術分野〕
本発明は、無線周波数の周波数変換装置に関する。特に
、周波数変換器と局部発振器との間に、局部発振器の高
次周波数（次数３以上少なくとも次数５以上）の受信ス
プリアスを減衰させる低域ろ波器を挿入して、上記周波
数変換器の信号帯域内に落ち込む局部発振器に起因する
出力スプリアスを減じた周波数変換装置に関する。
〔従来技術の説明〕
第１図は従来例の周波数変換装置のブロック構成図、第
２図はその低域通過ろ波器の減衰特性を示す図、第３図
は実際の低域通過ろ波器の減衰特性を示す図である。第
１図において、１．３は帯域通過ろ波器、２はミキサ、
４は局部発振器、６は低域通過ろ波器、ＲＦは入力信号
、ＩＦは出力信号、ＬＯは局部発振信号である。第２図
において、ｆＬｏは局部発振周波数、ｆｃｌ は遮断周
波数である。第３図から明らかなように、遮断周波数は
約１．６ ＧＨｚであり、減衰量がＯｄＢとなる周波数
は約７．４ ＧＤ３であり、減衰量がＯｄＢになる周波
数は、遮断周波数の約４．６倍程度である。一般の低域
通過ろ波器においては、減衰量がＯｄＢになる周波数は
、せいぜい遮断周波数の約５倍程度である。一方、周波
数変換装置の受信スプリアスで通信信号の信号帯域内に
落込む出力スプリアスの周波数をｆ（ｆとすると、出カ
スブリアス周波数ｆｔ！は（１１式によって定義される
。
ｌ ｆｃｆ ｌ ＝ ｍ ｆｓｐ ：！：ｎｉＬ、（、
−−−−−−（１）ここで、ｍ、ｎは整数、ｆｓｐは受
信スプリアス周波数である。
１１１式から明らかなように、第１図に示す従来例の周
波数変換器の構成では、低域通過ろ波器５の減衰特性が
遮断周波数の約５倍程度までである。
微弱信号を受信する場合に局部発振器４の高次（次数３
以上少なくとも次数５以上）の受信スプリアス周波数ｈ
Ｐによって周波数変換器出力部の通信信号帯域内に出カ
スブリアスが落込む重大な欠点があった。したがって、
このような場合には通信系の性能に重大な劣化をもたら
すことになる。
［文献〕
” ＭＩＣＲＯＷＡＶＥ ＦＩＬＴＥＲＳ、 ＩＭＰＥ
ＤＡＮＣＥ−ＭＡＴＣＨＩＮＧＮＢＴＷＯＲＫＳ、 Ａ
ＮＤ Ｃ０ＵＰＬＩＮＧ ５ＴＲＵＣＴＵＲＥＳ″ＣＨ
ＡＰＴＥＲ７，ＦＩＧ ７．０５−３． ｐｐ３９４゜
[Technical field to which the invention pertains] The present invention relates to a radio frequency frequency conversion device. In particular, a low-pass filter is inserted between the frequency converter and the local oscillator to attenuate reception spurious signals of high-order frequencies (order 3 or higher, at least order 5 or higher) of the local oscillator. The present invention relates to a frequency conversion device that reduces output spurious caused by a local oscillator falling within the band. [Description of Prior Art] Figure 1 is a block diagram of a conventional frequency converter, Figure 2 is a diagram showing the attenuation characteristics of its low-pass filter, and Figure 3 is an actual low-pass filter. FIG. In Figure 1, 1.3 is a bandpass filter, 2 is a mixer,
4 is a local oscillator, 6 is a low-pass filter, RF is an input signal, IF is an output signal, and LO is a local oscillation signal. In FIG. 2, fLo is the local oscillation frequency and fcl is the cutoff frequency. As is clear from Figure 3, the cutoff frequency is approximately 1.6 GHz, the frequency at which the amount of attenuation becomes OdB is approximately 7.4 GD3, and the frequency at which the amount of attenuation becomes OdB is approximately 4 GHz of the cutoff frequency. .6 times as much. In a general low-pass filter, the frequency at which the amount of attenuation becomes O dB is about five times the cutoff frequency at most. On the other hand, if the frequency of the output spurious which is a received spurious of the frequency converter and falls within the signal band of the communication signal is f (f), then the output cascading spurious frequency ft! is defined by (Equation 11): l fcf l = m fsp : !:niL,(,
--------(1) Here, m and n are integers, and fsp is the reception spurious frequency. As is clear from Equation 111, in the configuration of the conventional frequency converter shown in FIG. 1, the attenuation characteristic of the low-pass filter 5 is up to about five times the cutoff frequency. When receiving a weak signal, the higher order (3rd order) of the local oscillator 4
or higher (at least order 5 or higher) reception spurious frequency h
There is a serious drawback in that the output cascading noise falls within the communication signal band of the frequency converter output section due to P. therefore,
In such a case, the performance of the communication system will be seriously degraded. [Literature] ” MICROWAVE FILTERS, IMPE
DANCE-MATCHING NBTWORKS, A
ND C0UPLING 5TRUCTURES”CH
APTER7, FIG 7.05-3. pp394゜
本発明は、上記の欠点を除去し、局部発振器に起因する
通信信号帯域内に落ち込む出カスブリアスを減じた周波
数変換装置を提供することを目的とする。
〔発明の特徴〕
本発明は、人力信号の周波数変換をする周波数変換器と
、この周波数変換器に局部発振信号を供給する局部発振
器と、この局部発振器の出力信号が上記周波数変換器に
供給される信号通路に挿入された第一の低域通過ろ波器
とを備えた周波数変換装置において、上記信号通路に上
記低域通過ろ波器と縦続に挿入され上記局部発振信号の
周波数の３倍以上の高調波を含む高次高調波の周波数を
減衰させる第二の低域通過ろ波器を備えたことを特徴と
する。
〔実施例による説明〕
本発明の実施例について図面を参照して説明する。
第４図は本発明−実施例周波数変換装置のブロック構成
図である。第４図において、第１図と同一の部分は同一
の符号で示す。入力端子から入力信号ＲＦが帯域通過ろ
波器１を介してミキサ２に接続され、ミキサ２から変換
された信号が帯域通過ろ波器３に接続され、帯域通過ろ
波器３から出力信号ＩＦが出力端子に接続される。
ここで本発明の特徴とするところは、周波数変換装置内
に３倍波低域通過ろ波器５を設け、局部発振器４から局
部発振信号ＬＯを端子を介して入力し、３倍波低域通過
ろ波器５から局部発振信号ＬＯが低域通過ろ波器６と端
子とを介してミキサ２に入力されるように構成されたこ
とを特徴とする。
このような構成の周波数変換装置の動作について説明す
る。第５図は本発明の周波数変換装置の３倍波低域通過
ろ波器の減衰特性を示す図であり、その遮断周波数ｒｃ
ｚは、局部発振周波数ｆ１．．．ｏの約３倍の周波数に
設定されているので、減衰量はおよそ周波数１５ ｆｂ
ｏまでのびている。
第６図は本発明の周波数変換装置の低域通過ろ波器およ
び３倍波低域通過ろ波器を合成した減衰特性を示す図で
ある。第６図において、１０は低域通過ろ波器６の減衰
特性、１１は３倍波低域通過ろ波器の減衰特性、１２は
合成した減衰特性を示す。
遮断周波数ｆｃ２が周波数３ Ｌｏ近傍に設定された３
倍波低域通過ろ波器５を設けるこ点によって５局部発振
器４の高次（次数３以上少なくとも５以上）の周波数に
起因する受信スプリアスを除去することができるのであ
るから、周波数変換装置の通信信号帯域内に落込む出力
スプリアスを減することができる。−例として６ ／’
４ Ｇｌｌｚ周波数変換装置の場合を以下に示す。入力
周波数ｆｔｎが６．３０５Ｇｌｌｚ±２０Ｍ１ｌｚ、出
力周波数ｆｏｕｔ が４．０８ＧＨｚ±２０ＭＩ＋２
、局部発振周波数ｆＬａＱが２．２２５ＧＩＩｚの場合
に、局部発振出力に周波数２１．８７５ＧＨｚの受信ス
プリアスが局部発振信号ＬＯと受信スプリアスとのＤＵ
比（ｄｅｓｉｒｅｄ−ｔｏ−ｕｎｄｅｓｉｒｅｄ ｓｉ
ｇｎａｌ ｒａｔｉｏ）が７０ｄＢで存在するときに、
この受信スプリアスと６／４ ＧＨ２周波数変換装置に
おいて発生する局部発振信号ＬＯの８倍波とにより、
ｆ、Ｌｆ ＝ ｆｓｒ８ Ｘ ｆｃｏ ＝ ４．０７５
ＧＨｚとなり出力帯域内に出力スプリアスが発生する
。
このときの出力信号ＩＦと出力スプリアスとのＤＵ比は
、受信信号ＲＦが＝６０ｄＢｍ、受信信号ＲＦに対する
変換損失が６ｄＢ、受信スプリアスに対する変換損失が
３３ｄＢとすると、局部発振信号ＬＯのレベルが＋１０
ｄＢｍであることから、次の通りとなる。
出力信号ＩＦのレヘル＝入力信号ＲＦのレベル−変換損
失＝ ６０−６ ＝’ ６６ｄＢｍ出カスプリアスのレ
ヘル＝局部発振信号ＬＯのレベル−局部発振信号ＬＯと
受信スプリアスとのＤＵ比−変換損失＝＋１０−７０
３３＝−９３ｄＢｍゆえに、出力信号ＩＦと出力スプリ
アスとのＤＵ比−−６６−（−９３） ＝２７ｄＢとな
る。
第７図は従来例の周波数変換装置の出力スプリアスレス
ポンスを示す図である。本発明の周波数変換装置を用い
て２１．８７５ＧＨｚの受信スプリアスを３０ｄＢ減衰
させると出力信号ＩＦと出力スプリアスとのＤＵ比は５
７ｄＢとなり出力スプリアスを改善することができる。
第８図は本発明の周波数変換装置の化カスブリアスレス
ポンスを示す図である。このように局部発振信号の３倍
波以上の受信スプリアスを３倍波低域通過ろ波器５を追
加して減衰させることにより、この装置は４ ＧＨｚ帯
の帯域内の出力スプリアスレベルを飛躍的に減少させる
ものである。
以上は３倍波以上の高次高調波を阻止する低域通過ろ波
器を追加するように説明したが、５倍波以上の高次高調
波を阻止する低域通過ろ波器を追加することによっても
相応の効果がある。
〔発明の効果〕
以上説明したように、本発明は、周波数変換器と局部発
振器との間に第二の低域通過ろ波器を設げることにより
、局部発振器の発信周波数の高次の周波数に起因する通
信信号帯域内に落ち込む出力スプリアスを大幅に減じる
ことができる優れたす】果がある。したがって周波数変
換装置の性能を大幅に向上させる利点がある。SUMMARY OF THE INVENTION It is an object of the present invention to provide a frequency conversion device that eliminates the above-mentioned drawbacks and reduces the output cuspid that falls within the communication signal band due to the local oscillator. [Features of the Invention] The present invention provides a frequency converter that converts the frequency of a human signal, a local oscillator that supplies a local oscillation signal to the frequency converter, and an output signal of the local oscillator that is supplied to the frequency converter. a first low-pass filter inserted in a signal path, the frequency converter comprising: a first low-pass filter inserted in the signal path in cascade with the low-pass filter; The present invention is characterized in that it includes a second low-pass filter that attenuates frequencies of high-order harmonics including the above harmonics. [Explanation based on Examples] Examples of the present invention will be described with reference to the drawings. FIG. 4 is a block diagram of a frequency conversion device according to an embodiment of the present invention. In FIG. 4, the same parts as in FIG. 1 are designated by the same reference numerals. An input signal RF from an input terminal is connected to a mixer 2 via a bandpass filter 1, a converted signal from the mixer 2 is connected to a bandpass filter 3, and an output signal IF from the bandpass filter 3 is connected. is connected to the output terminal. Here, the feature of the present invention is that a third harmonic low pass filter 5 is provided in the frequency converter, the local oscillation signal LO is inputted from the local oscillator 4 through a terminal, and the third harmonic low pass filter 5 is provided in the frequency converter. It is characterized in that the local oscillation signal LO is input from the pass filter 5 to the mixer 2 via the low pass filter 6 and a terminal. The operation of the frequency conversion device having such a configuration will be explained. FIG. 5 is a diagram showing the attenuation characteristics of the third harmonic low-pass filter of the frequency converter of the present invention, and its cutoff frequency rc
z is the local oscillation frequency f1. ．． ．． Since the frequency is set to approximately 3 times that of o, the amount of attenuation is approximately 15 fb
It extends to o. FIG. 6 is a diagram showing the attenuation characteristics obtained by combining the low-pass filter and the 3rd harmonic low-pass filter of the frequency conversion device of the present invention. In FIG. 6, 10 indicates the attenuation characteristic of the low-pass filter 6, 11 indicates the attenuation characteristic of the third harmonic low-pass filter, and 12 indicates the combined attenuation characteristic. Cutoff frequency fc2 is set near frequency 3 Lo
By providing the harmonic low-pass filter 5, reception spurious caused by high-order (order 3 or higher and at least 5 or higher) frequencies of the local oscillator 4 can be removed. Output spurious that falls within the communication signal band can be reduced. - As an example 6/'
The case of the 4 Gllz frequency conversion device is shown below. Input frequency ftn is 6.305Gllz±20M1lz, output frequency fout is 4.08GHz±20MI+2
, when the local oscillation frequency fLaQ is 2.225 GIIz, the reception spurious with a frequency of 21.875 GHz is the DU of the local oscillation signal LO and the reception spurious in the local oscillation output.
desired-to-undesired si
gnal ratio) exists at 70 dB,
Due to this reception spurious and the 8th harmonic of the local oscillation signal LO generated in the 6/4 GH2 frequency converter, f, Lf = fsr8 X fco = 4.075
GHz, and output spurious occurs within the output band. The DU ratio between the output signal IF and the output spurious at this time is, assuming that the received signal RF is 60 dBm, the conversion loss for the received signal RF is 6 dB, and the conversion loss for the received spurious is 33 dB, the level of the local oscillation signal LO is +10 dBm.
Since it is dBm, it is as follows. Level of output signal IF = Level of input signal RF - Conversion loss = 60-6 = ' Level of 66 dBm output cusp = Level of local oscillation signal LO - DU ratio between local oscillation signal LO and reception spurious - Conversion loss = +10 -70
33=-93 dBm, therefore, the DU ratio between the output signal IF and the output spurious is -66-(-93)=27 dB. FIG. 7 is a diagram showing an output spurious response of a conventional frequency conversion device. When the frequency conversion device of the present invention is used to attenuate the reception spurious at 21.875 GHz by 30 dB, the DU ratio between the output signal IF and the output spurious is 5.
7 dB, which can improve the output spurious. FIG. 8 is a diagram showing the cascading response of the frequency conversion device of the present invention. By adding the third harmonic low-pass filter 5 to attenuate the received spurious waves of the third harmonic or higher of the local oscillation signal in this way, this device can dramatically reduce the output spurious level within the 4 GHz band. This will reduce the The above explanation was about adding a low-pass filter that blocks high-order harmonics of the 3rd harmonic and above, but it is also necessary to add a low-pass filter that blocks high-order harmonics of the 5th harmonic and above. This also has a corresponding effect. [Effects of the Invention] As explained above, the present invention provides a second low-pass filter between the frequency converter and the local oscillator, thereby reducing the high-order oscillation frequency of the local oscillator. This has the excellent effect of significantly reducing output spurious noise that falls within the communication signal band due to frequency. Therefore, there is an advantage that the performance of the frequency conversion device is greatly improved.
第１図は従来例の周波数変換装置のプロ・ツク構成図。
第２図はその低域通過ろ波器の減衰特性を示す図。
第３図は一般の低域通過ろ波器の遮断周波数と帯域外減
衰量との関係を表す減衰特性を示す図。
第４図は本発明一実施例周波数変換装置のブロック構成
図。
第５図はその３倍波低域通過ろ波器の減衰特性を示す図
。
第６図は本発明の周波数変換装置の低域通過ろ波器と３
倍波低域通過ろ波器とを合成した減衰特性を示す図。
第７図は従来例の周波数変換装置の化カスブリアスレス
ポンスを示す図。
第８図は本発明の周波数変換装置の出力スプリアスレス
ポンスを示す図。
１．３・・・帯域通過ろ波器、２・・ベキサ、４局部発
振器、５・・・３倍波低域通過ろ波器、６・・・低域通
過ろ波器、ｆ＝／・・・出力スプリアス周波数、ｆ、ｉ
・・・入力周波数、ｒＬｏ・・・局部発振周波数、ｔｏ
、ｔＬ ・・・出力周波数、ｆＳ、・・・受信スプリア
ス周波数、ＩＦ・・・出力信号、ＬＯ・・・局部発振信
号、ＲＦ・・・入力信号。
特許出願人 日本電気株式会社 ５、
代理人 弁理士 井 出 直 孝 、：［・
菖 １ 図
□周麦牧
蔦 ２ ロ
→周ｉ数（Ｇｃ）
第 ３ 図
箔 ４図
不５ 図
一一伽＠麦数−
肩 ６ ロ
ー周″Ｌ狡
箔 ８ 図FIG. 1 is a block diagram of a conventional frequency conversion device. FIG. 2 is a diagram showing the attenuation characteristics of the low-pass filter. FIG. 3 is a diagram showing attenuation characteristics representing the relationship between cutoff frequency and out-of-band attenuation of a general low-pass filter. FIG. 4 is a block diagram of a frequency conversion device according to an embodiment of the present invention. FIG. 5 is a diagram showing the attenuation characteristics of the third harmonic low-pass filter. Figure 6 shows the low-pass filter and 3 of the frequency converter of the present invention.
The figure which shows the attenuation characteristic combined with a harmonic low-pass filter. FIG. 7 is a diagram showing the cascading response of a conventional frequency conversion device. FIG. 8 is a diagram showing the output spurious response of the frequency conversion device of the present invention. 1.3...Band pass filter, 2...Bex, 4 local oscillator, 5...3rd harmonic low pass filter, 6...Low pass filter, f=/... ...Output spurious frequency, f, i
...Input frequency, rLo...Local oscillation frequency, to
, tL...output frequency, fS,...reception spurious frequency, IF...output signal, LO...local oscillation signal, RF...input signal. Patent applicant: NEC Corporation 5. Agent: Naotaka Ide, patent attorney: [・ Iris 1 Figure □ Shumugi Makitsuta 2 Ro → Shumui number (Gc) Figure 3 Haku 4 Figure Fu 5 Figure 11 @ Mugi Number - Shoulder 6 Low circumference "L Kouhaku 8 Figure
Claims (1)
の周波数変換器に局部発振信号を供給する局部発振器と
、 この局部発振器の出力信号が上記周波数変換器に供給さ
れる信号通路に挿入された第一の低域通過ろ波器と を備えた周波数変換装置において、 上記信号通路に上記低域通過ろ波器と縦続に挿入され上
記局部発振信号の周波数の３倍以上の高調波を含む高次
高調波の周波数を減衰させる第二の低域通過ろ波器 を備えたことを特徴とする周波数変換装置。[Claims] (11) A frequency converter that converts the frequency of an input signal, a local oscillator that supplies a local oscillation signal to this frequency converter, and an output signal of this local oscillator that is supplied to the frequency converter. a first low-pass filter inserted in a signal path, the frequency converter comprising: a first low-pass filter inserted in the signal path in cascade with the low-pass filter; A frequency conversion device comprising a second low-pass filter that attenuates frequencies of high-order harmonics including harmonics of.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3124284A JPS60174505A (en) | 1984-02-20 | 1984-02-20 | Frequency converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3124284A JPS60174505A (en) | 1984-02-20 | 1984-02-20 | Frequency converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS60174505A true JPS60174505A (en) | 1985-09-07 |
Family
ID=12325910
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3124284A Pending JPS60174505A (en) | 1984-02-20 | 1984-02-20 | Frequency converter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60174505A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6421517U (en) * | 1987-07-30 | 1989-02-02 | ||
| US5054118A (en) * | 1989-03-02 | 1991-10-01 | Motorola, Inc. | Balanced mixer utilizing filters |
| EP0929146A1 (en) * | 1998-01-12 | 1999-07-14 | Alps Electric Co., Ltd. | Tuner for satellite broadcasting receiver |
| EP1014576A2 (en) * | 1998-12-14 | 2000-06-28 | Deutsche Thomson-Brandt Gmbh | Method for driving a receiver stage and respective apparatus |
-
1984
- 1984-02-20 JP JP3124284A patent/JPS60174505A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6421517U (en) * | 1987-07-30 | 1989-02-02 | ||
| JPH0336095Y2 (en) * | 1987-07-30 | 1991-07-31 | ||
| US5054118A (en) * | 1989-03-02 | 1991-10-01 | Motorola, Inc. | Balanced mixer utilizing filters |
| EP0929146A1 (en) * | 1998-01-12 | 1999-07-14 | Alps Electric Co., Ltd. | Tuner for satellite broadcasting receiver |
| US6272312B1 (en) | 1998-01-12 | 2001-08-07 | Alps Electric Co., Ltd. | Satellite broadcasting receiving tuner which inhibits interference caused by satellite broadcast signals having one octave higher frequency band |
| EP1014576A2 (en) * | 1998-12-14 | 2000-06-28 | Deutsche Thomson-Brandt Gmbh | Method for driving a receiver stage and respective apparatus |
| EP1014576A3 (en) * | 1998-12-14 | 2003-01-29 | Deutsche Thomson-Brandt Gmbh | Method for driving a receiver stage and respective apparatus |
| US7164896B2 (en) | 1998-12-14 | 2007-01-16 | Thomson Licensing | Method for driving a receiver stage and respective apparatus |
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