JP2822461B2 - Temperature characteristic compensation method for SAW intermediate frequency filter - Google Patents
Temperature characteristic compensation method for SAW intermediate frequency filterInfo
- Publication number
- JP2822461B2 JP2822461B2 JP1184913A JP18491389A JP2822461B2 JP 2822461 B2 JP2822461 B2 JP 2822461B2 JP 1184913 A JP1184913 A JP 1184913A JP 18491389 A JP18491389 A JP 18491389A JP 2822461 B2 JP2822461 B2 JP 2822461B2
- Authority
- JP
- Japan
- Prior art keywords
- intermediate frequency
- filter
- signal
- frequency
- saw
- 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.)
- Expired - Lifetime
Links
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は第１中間周波フィルタとしてSAWフィルタを
用いたダブルスーパーヘテロダイン受信機に関する。Description: TECHNICAL FIELD The present invention relates to a double superheterodyne receiver using a SAW filter as a first intermediate frequency filter.
自動車電話等のダブルスーパーヘテロダイン受信機に
おいては、数十MHzの第１中間周波数を使用しておい、
この周波数帯に適用するSAW（バンド・パス）フィルタ
としては、従来ST−カット水晶上に形成されたものを使
用している。In a double superheterodyne receiver such as a car telephone, a first intermediate frequency of several tens of MHz is used,
As a SAW (band pass) filter applied to this frequency band, a filter formed on an ST-cut quartz crystal is conventionally used.
上述した従来のSAWフィルタは、その中心周波数の温
度変動が−30℃〜＋65℃の範囲で約100ppmと大きく（第
５図）、このように広い温度範囲でバンド・パス・フィ
ルタとして用いるためには、温度変動を見込んで所要通
過帯域巾と比べて必要以上に広帯域のフィルタを用いる
必要があった。そしてこのSAWフィルタが広帯域である
ために、隣接チャンネル波等からの妨害を受け易いとい
う欠点があった（第４図）。The above-described conventional SAW filter has a large temperature fluctuation of about 100 ppm in the center frequency range of -30 ° C. to + 65 ° C. (FIG. 5), and is required to be used as a band-pass filter in such a wide temperature range. Has required the use of a filter having a wider band than necessary in view of temperature fluctuations. Since the SAW filter has a wide band, there is a drawback that the SAW filter is susceptible to interference from adjacent channel waves or the like (FIG. 4).
本発明の目的は前記課題を解決したSAW中間周波フィ
ルタの温度特性補償方式を提供することにある。An object of the present invention is to provide a temperature characteristic compensation method for a SAW intermediate frequency filter that solves the above-mentioned problems.
前記目的を達成するため、本発明に係るSAW中間周波
フィルタの温度特性補償方式は第１中間周波フィルタと
してSAWフィルタを用いたダブルスーパーヘテロダイン
受信機において、前記SAWフィルタの中心周波数温度特
性と類似した傾向の発振周波数温度特性を持ち、第１の
局部発振信号を出力する第１局部発振器と、受信波と、
前記第１の局部発振信号とを混合して第１の中間周波数
信号を出力する第１の混合手段と、第２の局部発振信号
を出力する第２の局部発振手段と、前記第１の中間周波
数信号を入力する前記SAWフィルタの出力信号と、前記
第２の局部発振信号とを混合して第２の中間周波数信号
を出力する第２の混合手段と、中心周波数の温度に対す
る影響が少なく、前記第２の中間周波数信号を入力する
第２の中間周波フィルタと、出力周波数の温度変動が小
さく、基準信号を出力する基準発振器と、前記基準信号
と前記第２の中間周波フィルタの出力信号の差に応じた
制御信号を前記第２局部発振器に供給する供給手段と、
を備え、前記第２局部発振器は、前記制御信号により、
前記SAWフィルタの出力周波数の変動を吸収し、前記第
２の中間周波数信号の周波数を一定に保つように制御さ
れることを特徴とする。To achieve the above object, a temperature characteristic compensation method of a SAW intermediate frequency filter according to the present invention is similar to the center frequency temperature characteristic of the SAW filter in a double superheterodyne receiver using a SAW filter as a first intermediate frequency filter. A first local oscillator having a tendency oscillation frequency temperature characteristic and outputting a first local oscillation signal;
A first mixing means for mixing the first local oscillation signal to output a first intermediate frequency signal, a second local oscillation means for outputting a second local oscillation signal, A second mixing means for mixing the output signal of the SAW filter for inputting a frequency signal and the second local oscillation signal to output a second intermediate frequency signal, and having a small influence on the temperature of the center frequency; A second intermediate frequency filter that inputs the second intermediate frequency signal, a reference oscillator that outputs a reference signal with a small temperature variation in output frequency, and a reference oscillator that outputs the reference signal and the output signal of the second intermediate frequency filter. Supply means for supplying a control signal corresponding to the difference to the second local oscillator;
Wherein the second local oscillator is controlled by the control signal,
It is characterized in that it is controlled so as to absorb fluctuations in the output frequency of the SAW filter and to keep the frequency of the second intermediate frequency signal constant.
以下、本発明の一実施例を図により説明する。 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
第１図は本発明の一実施例を示すブロック図である。 FIG. 1 is a block diagram showing one embodiment of the present invention.
図において、１は第１混合器、２は第２混合器、３は
第１中間周波フィルタ（SAW）、４は第２中間周波フィ
ルタ、５は中間周波増幅器、６は第２局部発振器であ
る。また、７は電圧制御発振器、８はプリスケーラ、９
はプログラマブル・カウンタ、10は第１位相比較器、11
は第１低域通過フィルタ、12は第１基準発振器である。
また、13は第２低域通過フィルタ、14は第２位相比較
器、15は第２基準発振器である。In the figure, 1 is a first mixer, 2 is a second mixer, 3 is a first intermediate frequency filter (SAW), 4 is a second intermediate frequency filter, 5 is an intermediate frequency amplifier, and 6 is a second local oscillator. . 7 is a voltage controlled oscillator, 8 is a prescaler, 9
Is a programmable counter, 10 is a first phase comparator, 11
Is a first low-pass filter, and 12 is a first reference oscillator.
Further, 13 is a second low-pass filter, 14 is a second phase comparator, and 15 is a second reference oscillator.
ここに、電圧制御発振器7,プリスケーラ8,プログラマ
ブル・カウンタ9,第１位相比較器10,第１低域通過フィ
ルタ11,第１基準発振器12から第１局部発振器16が構成
され、該第１局部発振器16はSAW中間周波フィルタ３の
中心周波数温度特性と類似した傾向の発振周波数温度特
性をもつ。Here, a first local oscillator 16 is constituted by a voltage controlled oscillator 7, a prescaler 8, a programmable counter 9, a first phase comparator 10, a first low-pass filter 11, and a first reference oscillator 12. The oscillator 16 has an oscillation frequency temperature characteristic having a tendency similar to the center frequency temperature characteristic of the SAW intermediate frequency filter 3.
SAW中間周波フィルタ３と類似した傾向の発振周波数
温度特性をもつ第１局部発振器16の出力Ｄは受信波Ａと
第１混合器１で混合され第１中間周波Ｂを出力する。受
信波Ａの周波数fRに対して第１局部発振波Ｄの周波数 を大きく設定すれば、第１中間周波Ｂの周波数 と同様の温度変動をすることになり、これは第１中間周
波フィルタ（SAWフィルタ）３の中心周波数温度変動の
傾向と類似する（第３図）。第３図は第１局部発振周波
数、第１中間周波数及びSAW第１中間周波フィルタ中心
周波数の温度特性と、温度変動を補償するために必要と
なる余分な帯域を示す図である。The output D of the first local oscillator 16 having an oscillation frequency temperature characteristic similar to that of the SAW intermediate frequency filter 3 is mixed with the received wave A by the first mixer 1 to output a first intermediate frequency B. The frequency of the first local oscillation wave D with respect to the frequency f R of the reception wave A Is set to be large, the frequency of the first intermediate frequency B , Which is similar to the tendency of the center frequency temperature fluctuation of the first intermediate frequency filter (SAW filter) 3 (FIG. 3). FIG. 3 is a diagram showing temperature characteristics of the first local oscillation frequency, the first intermediate frequency, and the center frequency of the SAW first intermediate frequency filter, and an extra band required to compensate for temperature fluctuation.
Ａは第１局部発振周波数の偏差 （＝第１基準発振器の周波数偏差）、 Ｂは第１中間周波数の偏差ΔIF1,Cは第１中間周波フ
ィルタ（SAW）の中心周波数偏差ΔＦを示し、 とΔIF1との間には の関係がある。A is the deviation of the first local oscillation frequency (= Frequency deviation of the first reference oscillator), B is the deviation ΔIF1 of the first intermediate frequency, C is the center frequency deviation ΔF of the first intermediate frequency filter (SAW), And between ΔIF1 There is a relationship.
またΔW1は従来の方式において必要となる温度変動補
償帯域であり、ΔW2,ΔW3は本発明の方式において必要
となる温度変動補償帯域（第２図）である。ΔW 1 is a temperature fluctuation compensation band required in the conventional method, and ΔW 2 and ΔW 3 are temperature fluctuation compensation bands (FIG. 2) required in the method of the present invention.
第１中間周波フィルタ３を通過した第１中間周波Ｂ′
は第２混合器２で第２局部発振波Ｅと混合され第２中間
周波Ｃを出力する。第２中間周波フィルタ４を通過した
第２中間周波Ｃ′は中間周波増幅器５で増幅された後、
後段へ伝達されるとともに第２位相比較器14へ入力され
る。出力周波数の温度変動が小さい第２基準発振器15の
出力と第２中間周波Ｃ″との位相差に応じた第２位相比
較器14の出力は第２低域通過フィルタ13を通して第２局
部発振器６の発振周波数制御端子に入力され、第２中間
周波数を一定に保つように第２局部発振周波数を制御す
る。The first intermediate frequency B 'that has passed through the first intermediate frequency filter 3
Is mixed with the second local oscillation wave E in the second mixer 2 to output a second intermediate frequency C. The second intermediate frequency C ′ that has passed through the second intermediate frequency filter 4 is amplified by the intermediate frequency amplifier 5,
The signal is transmitted to the subsequent stage and is input to the second phase comparator 14. The output of the second phase comparator 14 corresponding to the phase difference between the output of the second reference oscillator 15 and the second intermediate frequency C ″ having a small temperature fluctuation of the output frequency is passed through the second low-pass filter 13 to the second local oscillator 6. And controls the second local oscillation frequency so as to keep the second intermediate frequency constant.
また、上記のような温度特性をもつ第１局部発振器16
は、これと同傾向の発振周波数温度特性をもつ第１基準
発振器12を用いたPLLループにより実現される（第３
図）。In addition, the first local oscillator 16 having the above-described temperature characteristics.
Is realized by a PLL loop using the first reference oscillator 12 having the same oscillation frequency-temperature characteristics as the above (third loop).
Figure).
〔発明の効果〕 以上説明したように本発明はSAW第１中間周波フィル
タと類似した周波数温度特性をもつ第１局部発振器を使
用することにより、第１中間周波数を常に第１中間周波
フィルタの帯域中心付近に保ち、その結果、SAWフィル
タを必要以上に広帯域に設計する必要がなくなり、隣接
チャンネル波等の妨害波を効率的に除去できるという効
果がある。また、第１図中間周波数の温度変動は、第２
中間周波数を一定に保つ制御ループを設け、第２局部発
振周波数を変化させることによって吸収でき、第２中間
周波フィルタは従来設計のままでよいという効果を有す
る。[Effect of the Invention] As described above, the present invention uses the first local oscillator having the frequency temperature characteristic similar to that of the SAW first intermediate frequency filter, so that the first intermediate frequency is always set to the band of the first intermediate frequency filter. Keeping it near the center, as a result, there is no need to design the SAW filter over an unnecessarily wide band, and there is an effect that interference waves such as adjacent channel waves can be efficiently removed. The temperature fluctuation of the intermediate frequency in FIG.
A control loop for keeping the intermediate frequency constant is provided, and can be absorbed by changing the second local oscillation frequency. This has the effect that the second intermediate frequency filter can be kept in the conventional design.
第１図は本発明の一実施例を示すブロック図、第２図は
本発明の方式を使った際にSAW第１中間周波フィルタが
必要とする帯域／減衰特性を示す図、第３図は第１局部
発振周波数、第１中間周波数及びSAW第１中間周波フィ
ルタ中心周波数の温度特性と、温度変動を補償するため
に必要となる余分な帯域を示す図、第４図は第１中間周
波フィルタとして用いられる従来のSAWフィルタの減衰
特性を示す図、第５図は通常第１中間周波フィルタとし
て用いられるSAWフィルタの中心周波数温度特性を示す
図である。 １……第１混合器、２……第２混合器 ３……第１中間周波フィルタ（SAW） ４……第２中間周波フィルタ ５……中間周波増幅器、６……第２局部発振器 ７……電圧制御発振器、８……プリスケーラ ９……プログラマブル・カウンタ 10……第１位相比較器 11……第１低域通過フィルタ 12……第１基準発振器 13……第２低域通過フィルタ 14……第２位相比較器、15……第２基準発振器 16……第１局部発振 Ａ……受信波、B,B′……第１中間周波 C,C′,C″……第２中間周波、Ｄ……第１局部発振波 Ｅ……第２局部発振波FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing band / attenuation characteristics required by a SAW first intermediate frequency filter when using the method of the present invention, and FIG. FIG. 4 is a diagram showing temperature characteristics of a first local oscillation frequency, a first intermediate frequency, and a center frequency of a SAW first intermediate frequency filter, and an extra band necessary for compensating for temperature fluctuation. FIG. FIG. 5 is a diagram showing the attenuation characteristics of a conventional SAW filter used as a filter, and FIG. 5 is a diagram showing the center frequency temperature characteristics of a SAW filter usually used as a first intermediate frequency filter. DESCRIPTION OF SYMBOLS 1 ... 1st mixer, 2 ... 2nd mixer 3 ... 1st intermediate frequency filter (SAW) 4 ... 2nd intermediate frequency filter 5 ... Intermediate frequency amplifier, 6 ... 2nd local oscillator 7 ... ... voltage controlled oscillator, 8 ... prescaler 9 ... programmable counter 10 ... first phase comparator 11 ... first low-pass filter 12 ... first reference oscillator 13 ... second low-pass filter 14 ... ... second phase comparator, 15 ... second reference oscillator 16 ... first local oscillation A ... received wave, B, B '... first intermediate frequency C, C', C "... second intermediate frequency , D ... first local oscillation wave E ... second local oscillation wave
Claims (1)
を用いたダブルスーパーヘテロダイン受信機において、 前記SAWフィルタの中心周波数温度特性と類似した傾向
の発振周波数温度特性を持ち、第１の局部発振信号を出
力する第１局部発振器と、 受信波と、前記第１の局部発振信号とを混合して第１の
中間周波数信号を出力する第１の混合手段と、 第２の局部発振信号を出力する第２の局部発振手段と、 前記第１の中間周波数信号を入力する前記SAWフィルタ
の出力信号と、前記第２の局部発振信号とを混合して第
２の中間周波数信号を出力する第２の混合手段と、 中心周波数の温度に対する影響が少なく、前記第２の中
間周波数信号を入力する第２の中間周波フィルタと、 出力周波数の温度変動が小さく、基準信号を出力する基
準発振器と、 前記基準信号と前記第２の中間周波フィルタの出力信号
の差に応じた制御信号を前記第２局部発振器に供給する
供給手段と、を備え、 前記第２局部発振器は、前記制御信号により、前記SAW
フィルタの出力周波数の変動を吸収し、前記第２の中間
周波数信号の周波数を一定に保つように制御されること
を特徴とするSAW中間周波フィルタの温度特性補償方
式。1. A double superheterodyne receiver using a SAW filter as a first intermediate frequency filter, wherein the first local oscillation signal has an oscillation frequency temperature characteristic having a tendency similar to the center frequency temperature characteristic of the SAW filter. A first local oscillator for outputting, a first mixing means for mixing a received wave and the first local oscillation signal to output a first intermediate frequency signal, and a second mixing means for outputting a second local oscillation signal A second local oscillator, and a second mixer for mixing the output signal of the SAW filter for inputting the first intermediate frequency signal and the second local oscillator signal and outputting a second intermediate frequency signal. Means, a second intermediate frequency filter for inputting the second intermediate frequency signal having a small influence on the temperature of the center frequency, and a reference oscillator for outputting a reference signal with a small temperature fluctuation of the output frequency. Supply means for supplying a control signal corresponding to a difference between the reference signal and the output signal of the second intermediate frequency filter to the second local oscillator, wherein the second local oscillator is configured to: SAW
A temperature characteristic compensation method for a SAW intermediate frequency filter, wherein the control is performed so as to absorb fluctuations in the output frequency of the filter and keep the frequency of the second intermediate frequency signal constant.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1184913A JP2822461B2 (en) | 1989-07-18 | 1989-07-18 | Temperature characteristic compensation method for SAW intermediate frequency filter |
| GB9015768A GB2234127B (en) | 1989-07-18 | 1990-07-18 | Double superheterodyne receiver with arrangement for compensating for temperature-dependent performance characteristics of a surface acoustic wave filter |
| US07/895,141 US5204972A (en) | 1989-07-18 | 1992-06-05 | Arrangement for compensating for temperature dependent performance characteristics of surface acoustic wave filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1184913A JP2822461B2 (en) | 1989-07-18 | 1989-07-18 | Temperature characteristic compensation method for SAW intermediate frequency filter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0349431A JPH0349431A (en) | 1991-03-04 |
| JP2822461B2 true JP2822461B2 (en) | 1998-11-11 |
Family
ID=16161525
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1184913A Expired - Lifetime JP2822461B2 (en) | 1989-07-18 | 1989-07-18 | Temperature characteristic compensation method for SAW intermediate frequency filter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2822461B2 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59133737A (en) * | 1983-01-20 | 1984-08-01 | Toshiba Corp | Intermediate frequency block |
| JPS59191921A (en) * | 1983-04-15 | 1984-10-31 | Hitachi Ltd | Oscillation frequency control circuit in tuner |
| JPS62250726A (en) * | 1986-04-23 | 1987-10-31 | Kinseki Kk | Local oscillator |
-
1989
- 1989-07-18 JP JP1184913A patent/JP2822461B2/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59133737A (en) * | 1983-01-20 | 1984-08-01 | Toshiba Corp | Intermediate frequency block |
| JPS59191921A (en) * | 1983-04-15 | 1984-10-31 | Hitachi Ltd | Oscillation frequency control circuit in tuner |
| JPS62250726A (en) * | 1986-04-23 | 1987-10-31 | Kinseki Kk | Local oscillator |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0349431A (en) | 1991-03-04 |
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