JPH04145723A - Local oscillator - Google Patents

Abstract

PURPOSE:To keep a phase difference between two output signals to 90 deg., or 0 deg. or 180 deg. by providing a frequency divider dividing a reference signal into two signals whose phase difference is 90 deg. and outputting the result and 2 systems of automatic phase control loop circuits to the oscillator. CONSTITUTION:An output of a reference oscillator 1 is divided by a frequency divider 2 and two frequency division output signals whose phase differs from 90 deg. are outputted. A voltage controlled oscillator 6A uses a frequency division signal of the oscillator 1 as a reference signal and forms an automatic phase control loop together with a frequency divider 5A, a pattern 3A and a loop filter 4A. Moreover, a voltage controlled oscillator 6B uses a frequency division signal of the oscillator 1 being phase-shifted by 90 deg. as a reference signal and forms an automatic phase control loop together with a frequency divider 5B, a pattern 3B and a loop filter 4B. When the frequency division number of the frequency dividers 5A, 5B is selected the same and an odd number frequency division ratio is adopted, the phase difference between the output signals 10, 11 is selected to be 90 deg. and when an even number frequency division ratio is adopted, the phase difference between the output signals 10, 11 is selected to be 0 deg. or 180 deg..

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は局部発振器に関し、特にイメージキャンセルコ
ンバータ、平衡変調器ＰＳ＃変復調器等に用いられる位
相差が９０”異なり、かつ、基準発振器に対して位相制
御された２つの局部発振信号を出力する局部発振器に関
する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a local oscillator, and in particular to a local oscillator that has a phase difference of 90" and that is used in image cancel converters, balanced modulators, PS# modems, etc. The present invention relates to a local oscillator that outputs two local oscillation signals that are phase-controlled.

〔従来の技術〕[Conventional technology]

従来の局部発振器は第２図のブロック図に示すように、
電圧制御発振器６の第１の分岐出力を分周器５で分周し
、その分周出力と基準発振器７の出力を位相比較器３で
比較し、その位相比較出力信号をループフィルタ４を通
して電圧制御発振器６の制御電圧として加えて自動位相
制御ループを形成している。この基準発振器７に対して
位相制御された電圧制御発振器６の第２の分岐出力を局
部発振器の出力信号１０とし、第３の分岐出力を位相推
移器８により９０°位相シフトして出力信号１１として
いた。A conventional local oscillator, as shown in the block diagram of Figure 2,
The first branch output of the voltage controlled oscillator 6 is divided by the frequency divider 5, the divided output and the output of the reference oscillator 7 are compared by the phase comparator 3, and the phase comparison output signal is passed through the loop filter 4 and converted into a voltage. It is added as a control voltage for the controlled oscillator 6 to form an automatic phase control loop. The second branch output of the voltage controlled oscillator 6 whose phase is controlled with respect to the reference oscillator 7 is used as the output signal 10 of the local oscillator, and the third branch output is phase-shifted by 90 degrees by the phase shifter 8 and output signal 11. It was.

〔発明が解決しようとする課題〕[Problem to be solved by the invention]

上述した従来の局部発振器は、９０°位相をシフトした
出力信号を得るために用いられる位相推移器がトランス
等を用いて構成した場合に、位相シフト量に周波数特性
を有しているので、周波数が変化する位相シフト量がず
れて９，０°の位相シフトが得られないという欠点があ
る。この位相シフト蓋のずれを直すために分周数を変え
て電圧制御発振器の発振周波数を変化させた際に出力信
号１０．１１の位相差が９０°からずれるという欠点が
ある。さらに位相推移器にトランス等を用いているので
、ＩＣ化かできないという欠点もある。In the conventional local oscillator described above, when the phase shifter used to obtain an output signal with a 90° phase shift is configured using a transformer, etc., the amount of phase shift has a frequency characteristic. There is a drawback that the amount of phase shift by which the phase shift changes is deviated, and a phase shift of 9.0 degrees cannot be obtained. There is a drawback that when the oscillation frequency of the voltage controlled oscillator is changed by changing the frequency division number in order to correct the shift of the phase shift lid, the phase difference of the output signals 10 and 11 deviates from 90 degrees. Furthermore, since a transformer or the like is used for the phase shifter, there is also the drawback that it can only be implemented as an IC.

〔課題を解決するための手段〕[Means to solve the problem]

本発明の局部発振器は、基準信号を出力する基準発振器
と、前記基準信号を入力して互いに９０度位相が異なる
第１および第２の分周信号を出力する分周器と、前記第
１および第２の分周信号をそれぞれ入力して互いに９０
度位相の異なる２つの出力信号をそれぞれ出力する２系
統の位相制御ループ回路とを有する。The local oscillator of the present invention includes: a reference oscillator that outputs a reference signal; a frequency divider that receives the reference signal and outputs first and second frequency-divided signals having phases different from each other by 90 degrees; Input the second frequency-divided signals and
It has two systems of phase control loop circuits that respectively output two output signals having different degrees and phases.

〔実施例〕〔Example〕

次に、本発明について図面を参照して説明する。 Next, the present invention will be explained with reference to the drawings.

第１図は本発明の一実施例のブロック図である。自動位
相制御器単信号を発振する基準発振器１の出力は、分周
器２で分周され互いに位相９０°異なる２つの分周出力
信号が出力される。FIG. 1 is a block diagram of one embodiment of the present invention. The output of a reference oscillator 1 which oscillates an automatic phase controller single signal is frequency-divided by a frequency divider 2, and two frequency-divided output signals having a phase difference of 90° from each other are output.

一方、電圧制御発振器６Ａの出力は２分岐され第１の分
岐出力９Ｂは分周器５Ａで分周されて位相比較器３Ａに
入力される。第２の分岐出力９Ａは局部発振器６Ａの出
力信号１０として出力される。位相比較器３Ａは分周器
２の出力信号と分周器５Ａの出力信号とを入力して位相
差が比較され、位相比較信号が出力される。この位相比
較信号はループフィルタ４Ａを径由して、電圧制御発振
器６Ａに周波数制御電圧として印加され位相引き込みが
行われる。すなわち、電圧制御発振器６Ａは、基準発振
器１の分周信号を基準として分周器５Ａ、位相比較器３
Ａ、ループフィルタ４Ａからなる自動位相制御ループが
形成される。電圧制御発振器６Ｂについては基準発振器
１の分周信号でかつ、９０°位相シフトした信号を基準
として前述と同様の構成で分周器５Ｂ、位相比較器３Ｂ
、ループフィルタ４Ｂからなる自動位相制御ループが形
成される。ここで分周器５Ａ、５Ｂの分周数を同じにし
、かつ、奇数分周にすることにより、出力信号１０．１
１との位相差を９０°にすることができる。又、分周器
５Ａ、５Ｂの分周数を同じにし、偶数分周にすることに
より、出力信号１０．１１の位相差をＯｏ又は１８０°
のどちらかにすることができる。On the other hand, the output of the voltage controlled oscillator 6A is branched into two, and the first branch output 9B is frequency-divided by the frequency divider 5A and input to the phase comparator 3A. The second branch output 9A is output as the output signal 10 of the local oscillator 6A. The phase comparator 3A inputs the output signal of the frequency divider 2 and the output signal of the frequency divider 5A, compares the phase difference, and outputs a phase comparison signal. This phase comparison signal passes through the loop filter 4A and is applied as a frequency control voltage to the voltage controlled oscillator 6A to perform phase pull-in. That is, the voltage controlled oscillator 6A uses the frequency divided signal of the reference oscillator 1 as a reference, and operates the frequency divider 5A and the phase comparator 3.
A, an automatic phase control loop consisting of a loop filter 4A is formed. Regarding the voltage controlled oscillator 6B, the frequency divider 5B and the phase comparator 3B are configured in the same manner as described above, using the frequency-divided signal of the reference oscillator 1 and a 90° phase-shifted signal as a reference.
, an automatic phase control loop consisting of the loop filter 4B is formed. Here, by making the frequency division numbers of the frequency dividers 5A and 5B the same and dividing the frequency by an odd number, the output signal 10.1
1 can be set to 90°. Also, by making the frequency division numbers of the frequency dividers 5A and 5B the same and dividing the frequency by an even number, the phase difference of the output signal 10.11 can be reduced to Oo or 180°.
It can be either.

〔発明の効果〕〔Effect of the invention〕

以上説明したように本発明は、基準信号を位相差が９０
°異なる２つの基準信号に分けて出力する分周器と、独
立の２系統の自動位相制御ループ回路とを備えることに
より、電圧制御発振器により生成される局部発振信号の
全ての周波数にわたって２出力信号間の位相差が正確に
９０°又は０°か１８０”に、保つことができる効果が
ある。又、トランス等を用いていないので、ＩＣ化が容
易であるという効果がある。As explained above, in the present invention, the reference signal has a phase difference of 90
°Equipped with a frequency divider that separates and outputs two different reference signals and two independent automatic phase control loop circuits, two output signals can be generated over all frequencies of the local oscillation signal generated by the voltage controlled oscillator. This has the advantage of being able to maintain the phase difference between 90°, 0°, or 180'' accurately.Also, since no transformer is used, it is easy to integrate into an IC.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明の一実施例のブロック図、第２図は従来
の局部発振器のブロック図である。 １．７・−・基準発振器、２，５．５Ａ、５Ｂ・・・分
周器、３．３Ａ、３Ｂ・・・位相比較器、４．４Ａ。FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional local oscillator. 1.7...Reference oscillator, 2,5.5A, 5B...Frequency divider, 3.3A, 3B...Phase comparator, 4.4A.

Claims (1)

【特許請求の範囲】 １、基準信号を出力する基準発振器と、前記基準信号を
入力して互いに９０度位相が異なる第１および第２の分
周信号を出力する分周器と、前記第１および第２の分周
信号をそれぞれ入力して互いに９０度位相の異なる２つ
の出力信号をそれぞれ出力する２系統の位相制御ループ
回路とを有することを特徴とする局部発振器。 ２、前記位相制御ループ回路のそれぞれが、電圧制御発
振器と、この電圧制御発振器の出力信号を分周する分周
回路と、この分周回路の出力信号と前記第１又は第２の
分周信号とを入力して位相差信号を出力する位相比較器
と、前記位相差信号がループフィルタを径由して前記電
圧制御発振器に帰還されることを特徴とする請求項１記
載の局部発振器。[Scope of Claims] 1. A reference oscillator that outputs a reference signal; a frequency divider that receives the reference signal and outputs first and second frequency-divided signals that are different in phase by 90 degrees from each other; and two systems of phase control loop circuits each inputting the second frequency-divided signal and outputting two output signals having phases different from each other by 90 degrees. 2. Each of the phase control loop circuits includes a voltage controlled oscillator, a frequency dividing circuit that divides the output signal of this voltage controlled oscillator, and an output signal of this frequency dividing circuit and the first or second frequency divided signal. 2. The local oscillator according to claim 1, further comprising a phase comparator which inputs a signal and outputs a phase difference signal, and said phase difference signal is fed back to said voltage controlled oscillator via a loop filter.