JPH0349431A - Temperature characteristic compensating system for saw intermediate frequency filter - Google Patents
Temperature characteristic compensating system for saw intermediate frequency filterInfo
- Publication number
- JPH0349431A JPH0349431A JP18491389A JP18491389A JPH0349431A JP H0349431 A JPH0349431 A JP H0349431A JP 18491389 A JP18491389 A JP 18491389A JP 18491389 A JP18491389 A JP 18491389A JP H0349431 A JPH0349431 A JP H0349431A
- Authority
- JP
- Japan
- Prior art keywords
- intermediate frequency
- filter
- wave
- saw
- temperature characteristic
- 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.)
- Granted
Links
- 230000010355 oscillation Effects 0.000 claims abstract description 16
- 238000000034 method Methods 0.000 claims description 4
- 238000010586 diagram Methods 0.000 description 8
- 238000007796 conventional method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
Landscapes
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
- Superheterodyne Receivers (AREA)
Abstract
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−パーヘテロダイン受信機に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a double superheterodyne receiver using a SAW filter as a first intermediate frequency filter.
【従来の技術］
自動車電話等のダブルス−パーヘテロダイン受信機にお
いては、数十Ｍ）ｌｚの第１中間周波数を使用しており
、この周波数帯に適応するＳＡＷ （バンド・バス）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。[Prior Art] A double superheterodyne receiver such as a car phone uses a first intermediate frequency of several tens of M)lz, and as a SAW (band bus) filter adapted to this frequency band, Conventionally, a device formed on ST-cut crystal is used.
（発明が解決しようとする課題）
上述した従来のＳＡＷフィルタは、その中心周波数の温
度変動が一３０℃〜＋６５℃の範囲で約１１００ｐｐと
大きく（第５図）、このように広い温度範囲でバンド・
バス・フィルタとして用いるためには、温度変動を見込
んで所要通過帯域中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。そりてこのＳＡυ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
受は易いという欠点があった（第４図）。(Problems to be Solved by the Invention) The conventional SAW filter described above has a large temperature fluctuation of its center frequency of about 1100 pp in the range of 130°C to +65°C (Fig. 5), band·
In order to use it as a bus filter, it was necessary to take into account temperature fluctuations and use a filter with a wider band than necessary compared to the required passband. Since this SAυ filter has a wide band, it has the disadvantage that it is susceptible to interference from adjacent channel waves, etc. (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 system for a SAW intermediate frequency filter that solves the above problems.
［課題を解決するための手段］
前記目的を達成するため、本発明に係るＳＡ％１１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−パーへテロ
ダイン受信機において、該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つ第
１局部発振器と、第２中間周波数を一定に保つように第
２局部発振器を制御するループとを有するものである。[Means for Solving the Problem] In order to achieve the above object, the temperature characteristic compensation method of the SA%11 intermediate frequency filter according to the present invention is a double superheterodyne receiver using a SAW filter as the first intermediate frequency filter. The first local oscillator has an oscillation frequency temperature characteristic having a tendency similar to the center frequency temperature characteristic of the SAW filter, and a loop that controls the second local oscillator so as to keep the second intermediate frequency constant. be.
［実施例］ 以下、本発明の−・実施例を図により説明する。[Example] Embodiments of the present invention will be described below 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. . Also, 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, voltage controlled oscillator 7. Prescaler 8° Programmable counter 9. First phase comparator 10° first low pass filter 11. A first local oscillator 16 is configured from the first reference oscillator 12, and the first local oscillator 16 has an oscillation frequency temperature characteristic that tends to be 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の出力りは受信波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。The output of the first local oscillator 16, which has an oscillation frequency temperature characteristic similar to that of the SAW intermediate frequency filter 3, is the received wave A.
and is mixed in the first mixer 1 to output the first intermediate frequency B.
受信波Ａの周波数ｒｌｌに対して第１局部発振波りの周
波数ｆ、４．を大きく設定すれば、第１中間周波Ｂの周
波数ＩＦＩ・ｆ、−ｆ、はｒＬｌ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 frequency f of the first local oscillation wave with respect to the frequency rll of the received wave A, 4. If set large, the frequencies IFI・f, -f of the first intermediate frequency B will have temperature fluctuations similar to rLl, which is due to the center frequency temperature fluctuation of the first intermediate frequency filter (SAW filter) 3. The trend is similar to that of (Figure 3). FIG. 3 is a diagram showing the temperature characteristics of the first local oscillation frequency, the first intermediate frequency, and the center frequency of the SAW first intermediate frequency filter, and the extra band required to compensate for temperature fluctuations.
Ａは第１局部発振周波数の偏差ΔｒＬ＋（＝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ΔＩＦＩ、 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、Δ
ｆＬ６とΔＩＦＩとの間には
ΔｆＬ、ｘｆい＝ΔＩＦＩ Ｘ ＩＦＩの関係がある。A is the deviation of the first local oscillation frequency ΔrL+ (=frequency deviation of the first reference oscillator), B is the deviation of the first intermediate frequency ΔIFI, C is the center frequency deviation ΔF of the first intermediate frequency filter (SAW), and Δ
There is a relationship between fL6 and ΔIFI as ΔfL, xf = ΔIFI x IFI.
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、Δ讐、ΔＷ、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。Further, ΔW1 is a temperature fluctuation compensation band required in the conventional method, and Δι, ΔW are temperature fluctuation compensation bands required in the method of the present invention (FIG. 2).
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１局部発振器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Ｉ５
の出力と第２中間周波Ｃ“ど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 first local oscillator E in the second mixer 2 and outputs the 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, and then transmitted to the subsequent stage and input to the second phase comparator 14. Second reference oscillator I5 with small temperature fluctuation in output frequency
The output of the second phase comparator 14 corresponding to the phase difference between the output of The second local oscillation frequency is controlled to keep 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Ｉ２を用いたＰ １．、Ｌループにより実現され
る（第３図）。In addition, the first local oscillator 16 having the above-mentioned temperature characteristics
is P1. using the first reference oscillator I2 which has the same oscillation frequency temperature characteristics as this. , L loop (Figure 3).
［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。[Effects of the Invention] As explained above, the present invention uses a first local oscillator having a frequency temperature characteristic similar to that of the SAW first intermediate frequency filter, so that the first intermediate frequency is always kept within the band of the first intermediate frequency filter. As a result, it is not necessary to design the SAW filter to have an unnecessarily wide band, and interference waves such as adjacent channel waves can be efficiently removed.
また、第１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。In addition, temperature fluctuations in the first intermediate frequency can be absorbed by providing a control loop that keeps the second intermediate frequency constant and changing the second local oscillation frequency, and the second intermediate frequency filter can remain in its conventional design. have an effect.
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
０・・・第１位相比較器
１・・・第１低域通過フィルタ
２・・・第１基準発振器
３・・・第２低域通過フィルタ
４・・・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
ｃ、 ｃ’、ｃ″・・・第２中間周波
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 the band/attenuation characteristics required by the SAW first intermediate frequency filter when using the method of the present invention, and Fig. 3 is a block diagram showing an embodiment of the present invention. A diagram showing the temperature characteristics of the first local oscillation frequency, first intermediate frequency, and center frequency of the SAW first intermediate frequency filter, and the extra band required to compensate for temperature fluctuations. Figure 4 shows the temperature characteristics of the first intermediate frequency filter. FIG. 5 is a diagram showing the attenuation characteristics of a conventional SAW filter used as the first intermediate frequency filter. FIG. 5 is a diagram showing the center frequency temperature characteristics of the SAW filter normally used as the first intermediate frequency filter. 1... First mixer 2... Second mixer 3.
...First intermediate frequency filter (SAW) 4...Second intermediate frequency filter 5...Intermediate frequency amplifier 6...Second local oscillator 7...Voltage controlled oscillator 8...Prescaler 9
...Programmable counter 0...First phase comparator 1...First low pass filter 2...First reference oscillator 3...Second low pass filter 4...Second phase Comparator 15...Second reference oscillator 16...First local oscillation A...Received wave c, c', c''...Second intermediate frequency E...Second local oscillation wave
Claims (1)
いたダブルスーパーヘテロダイン受信機において、該Ｓ
ＡＷ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つ第１局部発振器と、第２中間周
波数を一定に保つように第２局部発振器を制御するルー
プとを有す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) In a double superheterodyne receiver using a SAW filter as the first intermediate frequency filter, the S
The first local oscillator has an oscillation frequency temperature characteristic similar to the center frequency temperature characteristic of the AW filter, and a loop that controls the second local oscillator so as to keep the second intermediate frequency constant. Temperature characteristic compensation method for SAW intermediate frequency filter.
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 true JPH0349431A (en) | 1991-03-04 |
| JP2822461B2 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 |
|---|---|
| JP2822461B2 (en) | 1998-11-11 |
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