JPS6020640A - Channel selection circuit - Google Patents
Channel selection circuitInfo
- Publication number
- JPS6020640A JPS6020640A JP12769783A JP12769783A JPS6020640A JP S6020640 A JPS6020640 A JP S6020640A JP 12769783 A JP12769783 A JP 12769783A JP 12769783 A JP12769783 A JP 12769783A JP S6020640 A JPS6020640 A JP S6020640A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- circuit
- frequency
- local oscillation
- difference
- 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
- H03D7/16—Multiple-frequency-changing
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Superheterodyne Receivers (AREA)
Abstract
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明は２個の局部発振回路と２個の混合回路を有する
周波数２重変換方式の受信機の選局回路に関するもので
ある。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a channel selection circuit for a frequency double conversion receiver having two local oscillation circuits and two mixing circuits.
２個の混合回路と２個の局部発振回路を有する周波数２
重変換方式の受信機（以下受信機と略す。）を用い希望
するチャネルの信号を選局するＰＬＬ周波数シンセサイ
ザ方式の選局回路の従来例を第１図例示す。同図におい
て、１は高周波信号入力端子、２は高周波増幅素子、３
は第１混合回路、４は第１の局部発振回路、５はバンド
パスフィル′り、６は第１１Ｆ（中間周波数）増幅回路
、７は第２混合回路、８は第２の局部発振回路、９は第
２１Ｆ増幅回路、１ｏは第２ＩＦ信号出力端子、１１は
チャネル選局回路、１２はエンコ一ダ、１３は基準発振
器、７４は第１プログラマブル分周器、１５は第２プロ
グラマブル分周器、１６は低相比較回路、１７は低域沖
波器、２ｏは第６混合回路、２１は差信号増幅器、２２
はグリスケーラである。Frequency 2 with 2 mixing circuits and 2 local oscillator circuits
FIG. 1 shows an example of a conventional PLL frequency synthesizer type tuning circuit that selects a desired channel signal using a multiple conversion type receiver (hereinafter referred to as receiver). In the figure, 1 is a high frequency signal input terminal, 2 is a high frequency amplification element, and 3 is a high frequency signal input terminal.
is a first mixing circuit, 4 is a first local oscillation circuit, 5 is a bandpass filter, 6 is an 11F (intermediate frequency) amplifier circuit, 7 is a second mixing circuit, 8 is a second local oscillation circuit, 9 is a 21st amplifier circuit, 1o is a second IF signal output terminal, 11 is a channel selection circuit, 12 is an encoder, 13 is a reference oscillator, 74 is a first programmable frequency divider, 15 is a second programmable frequency divider , 16 is a low phase comparison circuit, 17 is a low-frequency wave transducer, 2o is a sixth mixing circuit, 21 is a difference signal amplifier, 22
is Gliscalera.
まず、高周波信号の受信動作について説明する。高周波
入力端子１から入力した信号周波数、ｈｐを高周波増幅
回路２で増幅した後、後述するチャネル選択動作に従っ
て第１局部発振周波数ｆ。ｓｃ＋を制御し、ｆＲＦとｆ
。ｓｃ、の和から固定の第１１Ｆ周波数ｆｔｐ＋ ｋ第
１混合回路６で作り、９ｉｔ１１Ｆ周波数ｆｌｙ、に等
しい高周波信号を通過させるバンドパスフィルタ５で受
信選択を行なつたあと第１１Ｆ増幅回路６で増幅し、第
２混合回路７で第１Ｆ周波数ｆｔｐ＋より高い周波数の
第２局部発振周波数ｆ。ＳＣ２と混合して差の周波数成
分を得て、第２１Ｆ周波数ｆｒｐ２ｆ作り出し、第２
ＩＰ増幅回路９で増幅して、出力端子１０から信号を出
力して、その後信号処理回路（図示せず）に入力する。First, the high frequency signal receiving operation will be explained. After the signal frequency hp input from the high frequency input terminal 1 is amplified by the high frequency amplifier circuit 2, the first local oscillation frequency f is set according to the channel selection operation described later. sc+, fRF and f
. A fixed 11F frequency ftp+k is generated by the first mixing circuit 6 from the sum of sc, and after reception selection is performed by the bandpass filter 5 that passes a high frequency signal equal to 9it11F frequency fly, it is amplified by the 11F amplifier circuit 6. Then, the second mixing circuit 7 generates a second local oscillation frequency f higher than the first F frequency ftp+. Mix with SC2 to obtain the difference frequency component, create the 21st F frequency frp2f, and
The signal is amplified by the IP amplifier circuit 9, outputted from the output terminal 10, and then inputted to a signal processing circuit (not shown).
次にチャネル選択動作について説明する。チャネル選択
回路１１で特定のチャネル番号の信号周波数ｆＲＦを選
択すると、チャネル番号をエンコーダ１２でチャネル番
号に応じてコード化して第１プログラマブル分周器１５
の分周比を変化させる。プログラマブル分周器１５には
、第３混合回路２０で、第１局部発振回路４の発振信号
ｆ。ｓｃ＋と第２局部発振回路８の発振信号ｆ。ＳＣ２
で混合して得た（ ｆｏｓｃ２ｆｏｓｃ＋ ）の差の周
波数信号を差信号増幅回路２１で増幅し、プリスケーラ
２２で分周した信号を入力して、第２のプログラマブル
分周器１５の分周比にしたがって分周して、位相比較器
１６に入力する。位相比較器１６には基準発振器１３の
出力を第１プログラマブル分周器１４で分周したものが
加えられており、この周波数に第２プログラマブル分周
器１５の出力の周波数が一致するように位相比較器１６
から制御信号を出力して低域沖波器１７で直流制御電圧
に変換して第１局部発振回路４の発振周波数を制御して
、チャネル選択器１１で選択されたチャネル番号の高周
波信号が受信できるように変化させて周波数シンセサイ
ザ一方式の選局動作が行なわれる。Next, the channel selection operation will be explained. When the channel selection circuit 11 selects the signal frequency fRF of a specific channel number, the encoder 12 encodes the channel number according to the channel number and sends it to the first programmable frequency divider 15.
change the frequency division ratio. The programmable frequency divider 15 receives the oscillation signal f of the first local oscillation circuit 4 through the third mixing circuit 20 . sc+ and the oscillation signal f of the second local oscillation circuit 8. SC2
The difference frequency signal of (fosc2fosc+) obtained by mixing is amplified by the difference signal amplification circuit 21, the frequency-divided signal is inputted to the prescaler 22, and the frequency signal is divided according to the frequency division ratio of the second programmable frequency divider 15. The frequency is divided and input to the phase comparator 16. The output of the reference oscillator 13 divided by the first programmable frequency divider 14 is added to the phase comparator 16, and the phase is adjusted so that the frequency of the output of the second programmable frequency divider 15 matches this frequency. Comparator 16
A control signal is outputted from the low frequency transducer 17 and converted into a DC control voltage to control the oscillation frequency of the first local oscillation circuit 4, so that the high frequency signal of the channel number selected by the channel selector 11 can be received. A one-way frequency synthesizer channel selection operation is performed by changing the frequency as follows.
この例においては、次のような問題点があった。まず、
第１に局部発振信号の高調波信号が混合回路に漏れ込み
、相互干渉妨害により、第１混合回路３あるいは第２混
合回路７などで、それぞれ第１１Ｆ周波数あるいは第２
ＩＦ周波数付近の信号が発生して、妨害を発生する。さ
らに第２には、第３の混合回路２ｏで混合した差の信号
周波数及びその高調波信号が８１発振回路４を経由して
第１混合回路６に漏れ込み、外部の希望しないＲＦ倍信
号混合され、第１ＩＦ周波数に等しい妨害信号を発生し
てしまう。第３は第２局部発振信号が、第３混合回路２
０及び第１局部発振回路４を経由して第１混合器３に漏
れ込み、そこで差の発振信号及びその高調波信号が発生
して、前述した第２の問題と同様な妨害が発生する。こ
れらのために従来の選局回路では受信機の不要妨害信号
の抑圧能力を低下させるという欠点があった。This example had the following problems. first,
First, harmonic signals of the local oscillation signal leak into the mixing circuit, and due to mutual interference, the first mixing circuit 3 or the second mixing circuit 7, etc., receive the 11F frequency or the second
Signals near the IF frequency are generated and cause interference. Furthermore, the second problem is that the difference signal frequency and its harmonics mixed in the third mixing circuit 2o leak into the first mixing circuit 6 via the 81 oscillation circuit 4, causing unwanted external RF multiplication signal mixing. and generates an interference signal equal to the first IF frequency. Thirdly, the second local oscillation signal is transmitted to the third mixing circuit 2.
0 and the first local oscillation circuit 4 to the first mixer 3, where a differential oscillation signal and its harmonic signals are generated, causing disturbance similar to the second problem described above. For these reasons, conventional channel selection circuits have the drawback of reducing the receiver's ability to suppress unnecessary interference signals.
本発明は上述した従来技術の欠点をなくし、受信機の不
要波妨害の抑圧能力を低下させることのない選局回路を
提供することにある。An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide a channel selection circuit that does not reduce the ability of a receiver to suppress unnecessary wave interference.
このため、本発明では、第１局部発振回路と差の周波数
信号を得る混合回路との間に、第１局部発振周波数範囲
の信号を通過させるバンドパスフィルタ及び、第２局部
発振信号の第１混合回路への漏洩を防止するバンドスト
ップフィルタあるいは、方向性結合器、また減衰器等を
挿入し、不要波を減衰させている。Therefore, in the present invention, a band-pass filter is provided between the first local oscillation circuit and the mixing circuit that obtains the difference frequency signal, and the band-pass filter that passes the signal in the first local oscillation frequency range, and the first Bandstop filters, directional couplers, or attenuators are inserted to prevent leakage into the mixing circuit, and unnecessary waves are attenuated.
〔発明の実施例）
第２図は本発明の第１の実施例を示すブロック図である
。同図において、第１図におけるのと同一の機能をもつ
ものについては同一の符号を付して説明を略する。同図
で２９は方向性結合器、３０はバンドパスフィルタ、３
１はバンドストップフィルタである。[Embodiment of the Invention] FIG. 2 is a block diagram showing a first embodiment of the invention. In this figure, parts having the same functions as those in FIG. 1 are designated by the same reference numerals, and the explanation thereof will be omitted. In the figure, 29 is a directional coupler, 30 is a bandpass filter, 3
1 is a bandstop filter.
同図で第１局部発振回路４の発振信号ｆ。５（”１の一
部は、第１局部発振信号ｆ。５Ｃ＋を混合回路２０へ伝
達するように方向性が与えられた方向性結合器３０を経
て、第１局部発振信号を通過させるバンドパスフィルタ
３０、第２局部発振信号を減衰させるバンドストップフ
ィルタ３１により不要信号を減衰させて第３混合回路２
０に伝達され第２局部発振回路８の発振信号ｆ。ＳＣ２
と差の周波数信号を得ている。その後差周波数信号は差
信号増幅器２１ヲ増幅されプリスケーラ２２に入力して
、第１図の従来例と同様な選局動作が行なわれる。In the figure, the oscillation signal f of the first local oscillation circuit 4 is shown. 5("1 is a bandpass which passes the first local oscillation signal through a directional coupler 30 which is given directionality so as to transmit the first local oscillation signal f.5C+ to the mixing circuit 20. A filter 30 and a band stop filter 31 that attenuates the second local oscillation signal attenuate unnecessary signals, and the third mixing circuit 2
0 and the oscillation signal f of the second local oscillation circuit 8. SC2
and the difference frequency signal is obtained. Thereafter, the difference frequency signal is amplified by a difference signal amplifier 21 and inputted to a prescaler 22, where a tuning operation similar to that of the conventional example shown in FIG. 1 is performed.
ここで、発振周波数と中間周波数（ＩＦ）、入力高周波
信号周波数との関連について、第３図にてさらに詳しく
述べる。Here, the relationship between the oscillation frequency, intermediate frequency (IF), and input high frequency signal frequency will be described in more detail with reference to FIG.
第３図は横軸は周波数をとり、周波数変換関係を示して
いる。入力高周波信号は最低周波数ｆＲＭＩＮと最高周
波数ｆＲＭＡＸの周波数範囲ｈｐにある。このｄ号は第
１局部発振信号ｆｏｓｃ＋により、ｆｌＦｌ” ｆＲＦ
＋ｆＯ５ｃ１の関係を満足するように変換されるので
、第１局部発振回路４の発振周波数は少なくとも、必要
最低発振周波数がｆｏｓｃ＋ Ｍｌ）／ ＝ ｆｔｐ＋
−ｆＲｐｘＡｘで最大発振周波数がｆｏｓｃ１ｘｉｘ
＝ｆｒｙ＋ ｆＲｐｈｔｚｎの範囲にあるＯ第１１Ｆ周
波数ｆｉｐ＋は、第２局部発振信号ｆｏｓｃ２を用い第
２ ＩＦ周波数ｆＩＦ２にｆｒｉｚ ＝ ｆｏｓｃ２−
ｆＩＦの関係により変換されるので、第２局部発振周波
数ｆ。ＳＣ２はｆｔｐ＋よりｆｚア、だげ高い周波数に
設定される。第３混合回路２１で得られる差の周波数信
号の周波数範囲はｆＲｙｚｓ ＋ ｆｒｉｚからｈｔｘ
ｉｘ ＋ ｆＩＦ２ の範囲にある。In FIG. 3, the horizontal axis represents frequency and shows the frequency conversion relationship. The input high frequency signal is in a frequency range hp between the lowest frequency fRMIN and the highest frequency fRMAX. This d signal is generated by the first local oscillation signal fosc+, flFl” fRF
Since the conversion is made to satisfy the relationship +fO5c1, the oscillation frequency of the first local oscillation circuit 4 is at least the required minimum oscillation frequency fosc+Ml)/=ftp+
- The maximum oscillation frequency is fosc1xix with fRpxAx
The 11th F frequency fip+ in the range of =fry+ fRphtzn is converted to the second IF frequency fIF2 using the second local oscillation signal fosc2.
Since it is converted according to the relationship fIF, the second local oscillation frequency f. SC2 is set to a frequency fz slightly higher than ftp+. The frequency range of the difference frequency signal obtained by the third mixing circuit 21 is from fRyzs + friz to htx
It is in the range of ix + fIF2.
！Ｅ４図は、バンドパスフィルタ３０及びノくンドスト
ップフィルタ６１の信号伝達特性を示す特性図である。! FIG. E4 is a characteristic diagram showing the signal transfer characteristics of the bandpass filter 30 and the stop filter 61.
同図で横軸は周波数、縦軸は減衰量である。バンドパス
フィルタ（ＢｐＦ ） ３１は、差の周波数信号あるい
はその低次の高調波信号を減衰させるとともに、第１局
部発振周波数ｆｏｓｃ＋あるいは第２局部発振周波数ｆ
Ｏ５ｃ２の高調波信号を減衰させるようになっており、
同図で点線で示される特性を有している。さらにバンド
ストップフィルタ（ＢＳＦ ） ３１は第２局部発振信
号ｆＯ５ｃ２を減衰し、第１局部発振信号を通過させる
ように同図で一点鎖線で示すような特性を有している。In the figure, the horizontal axis is frequency and the vertical axis is attenuation. The bandpass filter (BpF) 31 attenuates the difference frequency signal or its lower harmonic signal, and also attenuates the first local oscillation frequency fosc+ or the second local oscillation frequency f
It is designed to attenuate the harmonic signal of O5c2,
It has the characteristics shown by the dotted line in the figure. Further, the band stop filter (BSF) 31 has characteristics as shown by the dashed line in the figure so as to attenuate the second local oscillation signal fO5c2 and pass the first local oscillation signal.
このため、第１局部発振回路を経由して、第１混合回路
３へ漏れ込む、差の周波数信号あるいはその高調波及び
、第１あるいは第２局部発振信号の高調波信号を阻止し
、第１混合回路３で不要波信号が作成されるのを防止し
、不要波抑圧特性を改善できる。Therefore, the difference frequency signal or its harmonics and the harmonics of the first or second local oscillation signal leaking into the first mixing circuit 3 via the first local oscillation circuit are blocked, and the first It is possible to prevent unnecessary wave signals from being created in the mixing circuit 3 and improve unnecessary wave suppression characteristics.
ここで方向性結合回路２９は、フェライト磁性体を用い
たアイソレータや、一方向伝達特性を有する増幅素子、
例えば、トランジスタ増幅器などにより構成され、第１
混合回路６への伝達方向との逆の信号漏れ込みを防止す
る。特にノ（ンドパスフィルタ３０の通過帯域周波数と
、差の周波数信号の高調波信号が重なる場合は不要波信
号の抑圧が不十分となるので、方向性結合器２９より漏
れを抑圧できる。Here, the directional coupling circuit 29 includes an isolator using a ferrite magnetic material, an amplifying element having a unidirectional transfer characteristic,
For example, the first
This prevents signal leakage to the mixing circuit 6 in the opposite direction to the transmission direction. In particular, when the passband frequency of the second pass filter 30 and the harmonic signal of the difference frequency signal overlap, unnecessary wave signals will not be suppressed sufficiently, so the directional coupler 29 can suppress leakage.
第５図は本発明の第２の実施例を示すブロック図で、第
１図、第２図におけるのと同様の機能を有するものは同
一符号を付して説明を略する。FIG. 5 is a block diagram showing a second embodiment of the present invention. Components having the same functions as those in FIGS. 1 and 2 are denoted by the same reference numerals, and explanations thereof will be omitted.
第５図で５０は分波器である。第５図で、第１局部発振
回路４の発振信号ｆｏｓｃ１は第２混合回路７に入力さ
れる。第２混合回路７では第１１Ｆ周波数ｆｔｐ＋を第
２局部発振回路８の発振信号ｆＯ５ｃ２と混合して得ら
れる第２ＩＦ周波数ｆＩＦ２と、第１局部発振信号ｆｏ
ｓｃ＋と第２局部発振信号ｆｑｓｃ２との差の周波数信
号を同時に変換して得ている。In FIG. 5, 50 is a duplexer. In FIG. 5, the oscillation signal fosc1 of the first local oscillation circuit 4 is input to the second mixing circuit 7. The second mixing circuit 7 generates a second IF frequency fIF2 obtained by mixing the 11F frequency ftp+ with the oscillation signal fO5c2 of the second local oscillation circuit 8, and a first local oscillation signal fo.
It is obtained by simultaneously converting the frequency signal of the difference between sc+ and the second local oscillation signal fqsc2.
それらの複合信号は分波器５０で第２ＩＦ信号ｆｌＦ２
を周波数分離して、第２ＩＦ増幅器９へ、また、それよ
り高い周波数の差の周波数信号を、分波器５０で同様に
分離して、差信号増幅器２１に伝達して、第１図の従来
例及び第２図に示す本発明の実施例と同様な選局動作を
行なう。Those composite signals are sent to the splitter 50 as a second IF signal flF2.
is frequency-separated and sent to the second IF amplifier 9, and a frequency signal with a higher frequency difference is similarly separated by the duplexer 50 and transmitted to the difference signal amplifier 21, thereby transmitting the signal to the second IF amplifier 9. The same channel selection operation as in the example and the embodiment of the present invention shown in FIG. 2 is performed.
本実施例では、第２局部発振回路７にはバンドパスフィ
ルタ３０により高調波信号が減衰された第１局部発振信
号が入力されるので、第２混合回路７では局部発振信号
の高調波どうしの妨害を阻止することができる。In this embodiment, the first local oscillation signal whose harmonic signals have been attenuated by the bandpass filter 30 is input to the second local oscillation circuit 7, so the second mixing circuit 7 inputs the first local oscillation signal whose harmonics are attenuated by the bandpass filter 30. interference can be prevented.
さらに、第１局部発振信号の注入信号レベルを減衰器（
図示せず）などにエリ低レベルとして第１１Ｆ周波数ｈ
ｐ＋に混変調妨害などを与えないようにしている。この
ため差の周波数の信号レベルは低下するが差信号増幅器
２１で増幅度を増し対応している。本実施例では、第６
の混合回路が不要であり、回路構成が簡単になっており
、さらに第２局部発振信号の第６混合回路までの引き回
し布線がなくなるなどして、局部発振信号の高調波信号
同士の不要波妨害をさらに改善できる効果を有する。Furthermore, an attenuator (
(not shown) etc., the 11th F frequency h is used as an ELI low level.
This is to prevent cross-modulation interference from occurring on p+. For this reason, the signal level of the difference frequency decreases, but the difference signal amplifier 21 increases the degree of amplification to cope with this. In this example, the sixth
This eliminates the need for a mixing circuit, simplifying the circuit configuration, and eliminates the need for routing the second local oscillation signal to the sixth mixing circuit. It has the effect of further improving interference.
なお、バンドパスフィルタは、バイパスフィルタとロー
パスフィルタとの構成で得られることは明らかで、本発
明の実施例では差の周波数信号を減衰させるバイパスフ
ィルタと局部発振信号の高調波信号を減衰させるローパ
スフィルタの組み合わせでも同様の効果が得られる。さ
らにバンドパスフィルタで第２局部発振信号を十分減衰
可能ならばバンドストップフィルタは不要である。また
、方向性結合器は不要波信号を減衰させるためのもので
あるが、バンドパスフィルタおよびバンドストップフィ
ルタ３１で不要波が抑圧され、しかも差の周波数信号の
第１局部発振周波数範囲と重なる高調波信号が十分小さ
い場合には不要である。Note that it is clear that a bandpass filter is obtained by a configuration of a bypass filter and a low-pass filter, and in the embodiment of the present invention, a bypass filter that attenuates the difference frequency signal and a low-pass filter that attenuates the harmonic signal of the local oscillation signal are used. A similar effect can be obtained by combining filters. Furthermore, if the second local oscillation signal can be sufficiently attenuated by the bandpass filter, the bandstop filter is not necessary. Further, the directional coupler is for attenuating unnecessary wave signals, and the band pass filter and band stop filter 31 suppress unnecessary waves, and moreover, the harmonics that overlap with the first local oscillation frequency range of the difference frequency signal are suppressed. This is not necessary if the wave signal is sufficiently small.
′ 以上の様に本発明によれば、第１局部発振信号と第
２局部発振信号の差の周波数信号を得る混合回路と第１
局部発振回路の間に第１および第２局部発振信号の高調
波及び混合器で得た差の周波数信号及びその高調波信号
を阻止するフィルタあるいは方向性結合器を挿入するこ
とにより、不要波信号の発生を防止して、不要波抑圧特
性の良好な選局回路を実現できる。' As described above, according to the present invention, the mixing circuit that obtains the frequency signal of the difference between the first local oscillation signal and the second local oscillation signal;
By inserting a filter or directional coupler between the local oscillation circuit to block the harmonics of the first and second local oscillation signals, the difference frequency signal obtained by the mixer, and the harmonics thereof, unnecessary wave signals can be eliminated. This makes it possible to realize a tuning circuit with good unnecessary wave suppression characteristics.
第１図は、従来の選局回路例を示すブロック図、第２図
は、本発明の第１の実施例を示す選局回路のブロック図
、第３図は、本発明の第１の実施例の受信機の周波数変
換を示す説明図、第４図は第１の実施例の内容を説明す
るためのフィルタの特性図、第５図は本発明の第２の実
施例を示す選局回路のブロック図である。
３：第１混合回路
４：第１局部発振回路
７：第２混合回路
８：第２局部発振回路
１６：位相比較器
２０：第６混合回路
２２ニブリスケーラ
第 １ 図
第ｚ 図
第３ 刀
第 ４ 図FIG. 1 is a block diagram showing an example of a conventional tuning circuit, FIG. 2 is a block diagram of a tuning circuit showing a first embodiment of the present invention, and FIG. 3 is a block diagram of a tuning circuit showing a first embodiment of the present invention. An explanatory diagram showing the frequency conversion of the example receiver, FIG. 4 is a filter characteristic diagram for explaining the contents of the first embodiment, and FIG. 5 is a tuning circuit showing the second embodiment of the present invention. FIG. 3: First mixing circuit 4: First local oscillation circuit 7: Second mixing circuit 8: Second local oscillation circuit 16: Phase comparator 20: Sixth mixing circuit 22 Nibri scaler No. 1 Figure z Figure 3 Katana No. 4 figure
Claims (1)
合して第１１Ｆ周波信号を出力する第１の混合回路と、
前記第１１Ｆ周波信号と第２局部発振回路からの出力を
混合して第２１Ｆ周波信号を出力する第２の混合回路と
、前記第１局部発振回路の発振周波数と第２局部発振回
路の発振周波数を入力されてその差の周波数信号を出力
する第３の混合回路と、その差の周波数信号を入力とす
るプログラマブル分周器と、該分周器からの分周出力と
基準発振器からの発振出力との位相比較を行なう位相比
較器と、該比較器の出力で前記第１局部発振回路の発振
周波数を制御するようにした位相ロックループ回路とを
有し、前記プログラマブル分周器に受信信号周波数に応
じた分局比を与えることにより信号選択を行なうように
した選局回路において、前記第１局部発振回路と第３混
合回路との間に、前記差の周波数信号及びその高調波信
号と、前記第１．第２の各局部発振回路の高調波発振信
号とを減衰させ、前記第１局部発振回路の基本発振周波
数信号を通過させるフィルタを挿入したことを特徴とす
る選局回路。 ２、特許請求の範囲第１項に記載の選局回路において、
前記第３混合回路と前記第２混合回路を一つの混合回路
で共用することを特徴とする選局回路。[Claims] 1) a first mixing circuit that mixes the high frequency input signal and the output from the first local oscillation circuit and outputs an 11F frequency signal;
a second mixing circuit that mixes the 11F frequency signal and the output from the second local oscillation circuit to output a 21F frequency signal; an oscillation frequency of the first local oscillation circuit and an oscillation frequency of the second local oscillation circuit; a third mixing circuit that inputs the frequency signal and outputs a frequency signal of the difference, a programmable frequency divider that receives the frequency signal of the difference as input, and a divided output from the frequency divider and an oscillation output from the reference oscillator. and a phase-locked loop circuit configured to control the oscillation frequency of the first local oscillation circuit using the output of the comparator, In the channel selection circuit which performs signal selection by giving a division ratio according to 1st. A tuning circuit characterized in that a filter is inserted that attenuates harmonic oscillation signals of each second local oscillation circuit and passes a fundamental oscillation frequency signal of the first local oscillation circuit. 2. In the tuning circuit according to claim 1,
A tuning circuit characterized in that the third mixing circuit and the second mixing circuit are shared by one mixing circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12769783A JPS6020640A (en) | 1983-07-15 | 1983-07-15 | Channel selection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12769783A JPS6020640A (en) | 1983-07-15 | 1983-07-15 | Channel selection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6020640A true JPS6020640A (en) | 1985-02-01 |
Family
ID=14966462
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12769783A Pending JPS6020640A (en) | 1983-07-15 | 1983-07-15 | Channel selection circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6020640A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007259211A (en) * | 2006-03-24 | 2007-10-04 | Nec Corp | Local oscillator and radio transceiver using it |
| US8384676B2 (en) | 2005-10-31 | 2013-02-26 | Toshihiko Kondo | Keyboard device and keyboard cover |
-
1983
- 1983-07-15 JP JP12769783A patent/JPS6020640A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8384676B2 (en) | 2005-10-31 | 2013-02-26 | Toshihiko Kondo | Keyboard device and keyboard cover |
| JP2007259211A (en) * | 2006-03-24 | 2007-10-04 | Nec Corp | Local oscillator and radio transceiver using it |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR920007089B1 (en) | Rf tuning circuit which provides image frequency rejection | |
| JPH0486139A (en) | Direct conversion receiver | |
| US4764979A (en) | Direct relay equipment | |
| JPH0152923B2 (en) | ||
| JPH09289467A (en) | High-frequency receiving circuit of mobile communication equipment | |
| JPH09219664A (en) | Radio transmitter-receiver | |
| JP3309904B2 (en) | Wireless transceiver | |
| JP2002300488A (en) | Dual-type digital television tuner | |
| JPS6020640A (en) | Channel selection circuit | |
| JPS6042943A (en) | Tuner | |
| JPS60174505A (en) | Frequency converter | |
| US5881054A (en) | Frequency division duplex transmitter which attenuates the difference between a receiving frequency an output frequency from a second oscillator | |
| JPH0488728A (en) | Radio transmitter-receiver | |
| JP2004088609A (en) | Frequency converter | |
| JPH11136151A (en) | Receiver and transmitter-receiver | |
| JPH01278132A (en) | Transmitter-receiver for satellite communication | |
| JPH03226022A (en) | High frequency filter | |
| JPH0551212B2 (en) | ||
| KR950013304B1 (en) | Cellular phone inter freguency circuit | |
| JPH07202743A (en) | Frequency converter | |
| JPS61125209A (en) | Method for improving intermodulation characteristic | |
| JPS63119308A (en) | Power amplifier | |
| JPH05102734A (en) | Coupling circuit for mixer | |
| JPH057162A (en) | Radio receiver | |
| JPS63146621A (en) | Low noise converter |