JPH03101418A - Frequency synthesizer - Google Patents

Frequency synthesizer

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Publication number
JPH03101418A
JPH03101418A JP1238641A JP23864189A JPH03101418A JP H03101418 A JPH03101418 A JP H03101418A JP 1238641 A JP1238641 A JP 1238641A JP 23864189 A JP23864189 A JP 23864189A JP H03101418 A JPH03101418 A JP H03101418A
Authority
JP
Japan
Prior art keywords
frequency
oscillator
circuit
division ratio
controller
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
Application number
JP1238641A
Other languages
Japanese (ja)
Inventor
Katsushi Yoshihara
吉原 勝志
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Engineering Ltd
Original Assignee
NEC Engineering Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by NEC Engineering Ltd filed Critical NEC Engineering Ltd
Priority to JP1238641A priority Critical patent/JPH03101418A/en
Publication of JPH03101418A publication Critical patent/JPH03101418A/en
Pending legal-status Critical Current

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  • Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)

Abstract

PURPOSE:To simplify the circuit constitution by providing a circuit shifting a frequency of a reference frequency oscillator attended with variable control of a frequency division ratio to a phase locked loop circuit provided with a controller capable of controlling the change in the frequency division ratio of a frequency divider. CONSTITUTION:A phase locked loop circuit comprising a reference frequency oscillator 1, a phase error detector 2, a loop filter 3, a voltage controlled oscillator 4, a frequency divider 6 and a controller 1 varying the frequency division ratio of the frequency divider 6 is provided additionally with a circuit shifting the frequency of the reference frequency oscillator 1 attended with the control of the frequency division ratio by the controller 7. Since the output frequency of the reference frequency oscillator 1 is shifted by a minute frequency attended with the control of the frequency division ratio in the phase locked loop circuit, the frequency with an optional frequency step is generated around an optional center frequency without use of a frequency conversion oscillator and a 2nd PLL circuit or the like. Thus, the circuit constitution is simplified.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は周波数分割通信用の周波数シンセサイザに関し
、特に回路構成の簡易化を図った周波数シンセサイザに
関する。
DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a frequency synthesizer for frequency division communication, and particularly to a frequency synthesizer with a simplified circuit configuration.

〔従来の技術〕[Conventional technology]

一般に無線通信、特に衛星通信においては、通信帯域が
規定されており、しかも周波数分割多重通信方式では、
その周波数分割のスロット周波数も規定されている。衛
星通信では、通常中間周波数(IF)が70MHzで通
信帯域が±18MH2、或いはIFが140MH,で帯
域が±36MH2が使用され、周波数分割のスロット周
波数間隔は、共に22.5KH,となっている。また、
この22.5KH。
Generally speaking, in wireless communications, especially in satellite communications, communication bands are specified, and in frequency division multiplexing communication systems,
The slot frequency of the frequency division is also specified. In satellite communications, the intermediate frequency (IF) is usually 70 MHz and the communication band is ±18 MH2, or the IF is 140 MHz and the band is ±36 MH2, and the slot frequency interval of frequency division is 22.5 KH in both cases. . Also,
This 22.5KH.

間隔は、IF=70MH,又は140MH,を中心にし
て決められている。
The interval is determined around IF=70MH or 140MH.

ところが、70MH2又は140MH2は、22.5K
H2の整数倍、となっていないため、1個の電圧制御発
振器で前記特性の周波数シンセサイザを構成することは
不可能であり、更に1個の発振器を用いてこれらの周波
数をミキサすることにより、所望の特性を得ていた。
However, 70MH2 or 140MH2 is 22.5K
Since it is not an integral multiple of H2, it is impossible to configure a frequency synthesizer with the above characteristics with one voltage controlled oscillator, and by mixing these frequencies using one oscillator, The desired characteristics were obtained.

従来のこの種の周波数シンセサイザの一例を第2図に示
す。図において、電圧制御発振器4の出力は分配器5に
より2分され、一方は分周器6に人力され、ここで電圧
制御発振器4の出力周波数が1/Hされた後、位相誤差
検出器2に人力される。また、この位相誤差検出器2へ
は基準周波数用発振器1からの基準周波数も人力されて
いる。
An example of a conventional frequency synthesizer of this type is shown in FIG. In the figure, the output of the voltage controlled oscillator 4 is divided into two by a divider 5, one is manually input to the frequency divider 6, where the output frequency of the voltage controlled oscillator 4 is 1/H, and then the phase error detector 2 is man-powered. Further, the reference frequency from the reference frequency oscillator 1 is also input manually to the phase error detector 2.

基準周波数は、この場合22.5KH,となる。位相誤
差検出器2で、これらの周波数の位相誤差が検出され、
この誤差信号はループフィルタ3を通って、前記電圧制
御発振器4へ入力される。これで、第1の位相同期回路
(P L L :  Phare Lock Loop
)が構成される。
The reference frequency is 22.5 KH in this case. The phase error detector 2 detects the phase errors of these frequencies,
This error signal passes through the loop filter 3 and is input to the voltage controlled oscillator 4. This completes the first phase lock loop (PLL).
) is configured.

電圧制御発振器4の出力を22.5KH2間隔で制御す
るのは、制御器7により分周器6のNの値を変えること
で行なえる。
The output of the voltage controlled oscillator 4 can be controlled at intervals of 22.5KH2 by changing the value of N of the frequency divider 6 using the controller 7.

このようにして得られた電圧制御発振器4の出力は、分
配器5を通ってミキサ12により、発振器11の周波数
とミキシングされる。このミキサ12の出力において、
IF=70MH2又は140MH2を中心にした22.
5KH2間隔の周波数シンセサイザが得られる。
The output of the voltage controlled oscillator 4 thus obtained passes through the distributor 5 and is mixed with the frequency of the oscillator 11 by the mixer 12. At the output of this mixer 12,
22. centered around IF=70MH2 or 140MH2.
A frequency synthesizer with 5KH2 intervals is obtained.

しかし、ミキサ12でミキシングによるイメージ周波数
及びスプリアスが発生するため、これらを除去するため
の第2の位相同期回路が用いられる。すなわち、ミキサ
12出力は、分周器13に入力されて1/M分周された
後、位相誤差検出器14に入力される。また、位相誤差
検出14には電圧制御発振器16の出力が分配器17を
通り、分周器18を通って入力される。位相誤差検出器
14でこれらの周波数の位相誤差が検出され、この誤差
信号はループフィルタ15を通って、電圧制御発振器1
6の制御電圧信号となる。
However, since the mixer 12 generates an image frequency and spurious due to mixing, a second phase locked circuit is used to remove these. That is, the mixer 12 output is input to the frequency divider 13 and divided by 1/M, and then input to the phase error detector 14. Further, the output of the voltage controlled oscillator 16 is inputted to the phase error detection 14 through a distributor 17 and a frequency divider 18 . The phase error detector 14 detects the phase errors of these frequencies, and this error signal passes through the loop filter 15 and is sent to the voltage controlled oscillator 1.
6 control voltage signal.

このようにして、ミキサ12の出力は第2PLL回路、
すなわちループフィルタ15の帯域により、イメージ周
波数及びスプリアス等の不要波が除去される。また、分
配器17の他方より周波数シンセサイザ出力が得られる
In this way, the output of the mixer 12 is transmitted to the second PLL circuit,
That is, the band of the loop filter 15 removes image frequencies and unnecessary waves such as spurious waves. Further, a frequency synthesizer output is obtained from the other side of the divider 17.

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

上述した従来の周波数シンセサイザは、IF=70MH
2又は140MH2を中心とした22.5KH。
The conventional frequency synthesizer mentioned above has an IF=70MH
22.5KH centered around 2 or 140MH2.

間隔の周波数ステップを実現するために、電圧制御発振
器の他に、局部発振器を必要としてこれらの周波数をミ
キシングし、更にそのミキシングにより発生するスプリ
アス等の不要波を取り除くために第2のPLL回路が必
要とされる。このため回路構成が大規模になるという問
題がある。
In order to realize interval frequency steps, a local oscillator is required in addition to the voltage controlled oscillator to mix these frequencies, and a second PLL circuit is used to remove spurious and other unnecessary waves generated by the mixing. Needed. Therefore, there is a problem that the circuit configuration becomes large-scale.

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

本発明の周波数シンセサイザは、分周器の分周比を変化
制御可能な制御器を備える位相同期回路に、分周比の変
化制御に伴って基準周波数用発振器の周波数を偏移させ
る回路を付設している。
The frequency synthesizer of the present invention has a phase synchronized circuit equipped with a controller capable of changing and controlling the division ratio of a frequency divider, and a circuit that shifts the frequency of a reference frequency oscillator in accordance with the control of changing the division ratio. are doing.

この回路は、制御器から出力されるデータを保持しかつ
出力するデータ保持器と、このデータをデジタル変換す
るアナログ−デジタル変換器と、デジタル信号の高周波
を除去する低域ろ波器とで構成し、低域ろ波器の出力を
基準周波数用発振器の周波数制御端子に入力させている
This circuit consists of a data holder that holds and outputs data output from the controller, an analog-to-digital converter that converts this data into digital data, and a low-pass filter that removes high frequencies from the digital signal. The output of the low-pass filter is input to the frequency control terminal of the reference frequency oscillator.

(作用〕 この構成では、例えば、基準周波数用発振器の発振周波
数を22.5KH2+Δfとし、かつこれに応じて分周
比を制御することで、T F =70M Hz又は14
0MH2を中心周波数とした22.5KH2ステツプの
周波数の生成を実現する。
(Function) In this configuration, for example, by setting the oscillation frequency of the reference frequency oscillator to 22.5 KH2+Δf and controlling the frequency division ratio accordingly, T F =70 MHz or 14
This realizes frequency generation of 22.5KH2 steps with 0MH2 as the center frequency.

〔実施例〕 次に、本発明を図面を参照して説明する。〔Example〕 Next, the present invention will be explained with reference to the drawings.

本発明の周波数シンセサイザの一実施例を第1図に示す
。なお、第2図と同一記号は、同−又は均等部分を示し
ている。即ち、1は基準周波数用発振器、2は位相誤差
検出器、3はループフィルタ、4は電圧制御発振器、5
は分配器、6は分周器である。これらによる第1のPL
L回路の動作はこれまでと同じであり、詳細な説明は省
略する。
An embodiment of the frequency synthesizer of the present invention is shown in FIG. Note that the same symbols as in FIG. 2 indicate the same or equivalent parts. That is, 1 is a reference frequency oscillator, 2 is a phase error detector, 3 is a loop filter, 4 is a voltage controlled oscillator, and 5
is a distributor, and 6 is a frequency divider. The first PL based on these
The operation of the L circuit is the same as before, and detailed explanation will be omitted.

そして、前記分周器6を制御する制御器7にデータ保持
器8.アナログ−デジタル変換器9、高周波成分除去用
低域通過ろ波器10を付設し、制御器7からデータをデ
ータ保持器8へ送り、そこでデータを保持した上でその
出力データを次のアナログ−デジタル変換器9へ入力し
てアナログ電圧に変換し、更に高調波成分除去用低域通
過ろ波器10を通して基準周波数用発振器1の周波数制
御用端子に入力させている。
A controller 7 that controls the frequency divider 6 has a data holder 8. An analog-to-digital converter 9 and a low-pass filter 10 for removing high frequency components are attached, and data is sent from the controller 7 to a data holder 8, where the data is held and the output data is sent to the next analog - The signal is inputted to a digital converter 9, converted into an analog voltage, and further passed through a low-pass filter 10 for removing harmonic components and inputted to a frequency control terminal of the reference frequency oscillator 1.

これにより、制御器7は分周器6の分周比を変化させる
と同時に、その出力データにより基準周波数用発振器1
の発振周波数を偏移させることが可能となる。ここで、
基準周波数用発振器1では、その発振周波数を22.5
KH2からΔfだけ偏移させている。
As a result, the controller 7 changes the frequency division ratio of the frequency divider 6, and at the same time changes the reference frequency oscillator 1 based on the output data.
It becomes possible to shift the oscillation frequency of. here,
The reference frequency oscillator 1 has an oscillation frequency of 22.5
It is shifted by Δf from KH2.

したがって、前記Δf量と、分周器6の分周比Nの関係
は、IF=70MH2帯の時、下式とする。
Therefore, the relationship between the Δf amount and the frequency division ratio N of the frequency divider 6 is expressed by the following formula when IF=70MH2 band.

(22,5KH2+Δf)(N、+N、)=52MHz
 +22.5KHz XN、・・・(1)ここで、No
は(22,5KH2+Δf′)×N0−52 M Hz
を満たす分周比、また、N1はO〜1600の範囲の分
周比である。
(22,5KH2+Δf)(N,+N,)=52MHz
+22.5KHz XN,... (1) Here, No
is (22,5KH2+Δf')×N0-52 MHz
N1 is a frequency division ratio in the range of 0 to 1600.

式(1)より、 となる。From formula (1), becomes.

制御器7は分周器6の分周比NをNo又はN1に制御す
るとともに、データ保持器8へも式(2)のΔfとN、
の関係を保つように、制御データを送出して基準周波数
用発振器1出力のΔfを制御する。
The controller 7 controls the frequency division ratio N of the frequency divider 6 to No or N1, and also inputs Δf and N of equation (2) to the data holder 8.
Control data is sent to control Δf of the reference frequency oscillator 1 output so as to maintain the relationship.

これにより、分配器5から出力される周波数を、70M
H2を中心とした22.5KH2ステツプに制御するこ
とができる。
As a result, the frequency output from the distributor 5 is changed to 70M
It can be controlled to 22.5KH2 steps centered on H2.

1 F= 140MH2帯についても同様に求められ下
式となる。
1 F = 140 MH2 band is similarly calculated and becomes the following formula.

ここで、Noは(22,5KH2+Δf ’ ) X 
N。
Here, No is (22,5KH2+Δf')
N.

= 104MH2を満たす分周比、N1は0〜3200
の範囲の分周比である。
= Frequency division ratio that satisfies 104MH2, N1 is 0 to 3200
is the frequency division ratio in the range of .

〔発明の効果〕〔Effect of the invention〕

以上説明したように本発明は、位相同期回路における分
周比の制御に伴って基準周波数用発振器の出力周波数を
微少周波数だけ偏移させているので、周波数変換用発振
器や第2のPLL回路等を用いることな(、任意の中心
周波数で任意の周波数ステップの周波数を生成すること
ができ、回路構成を容易なものにすることができる。
As explained above, in the present invention, the output frequency of the reference frequency oscillator is shifted by a minute frequency in accordance with the control of the frequency division ratio in the phase locked circuit, so that the frequency conversion oscillator, the second PLL circuit, etc. By using (, it is possible to generate a frequency with an arbitrary frequency step at an arbitrary center frequency, and the circuit configuration can be simplified.

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

第1図は本発明の一実施例のブロック回路図、第2図は
従来の周波数シンセサイザのブロック回路図である。
FIG. 1 is a block circuit diagram of an embodiment of the present invention, and FIG. 2 is a block circuit diagram of a conventional frequency synthesizer.

Claims (1)

【特許請求の範囲】 1、所要の中心周波数で所要の周波数帯域ステップの周
波数を発生する周波数シンセサイザにおいて、基準周波
数用発振器、位相誤差検出器、ループフィルタ、電圧制
御発振器、分周器、及びこの分周器の分周比を変化制御
する制御器で構成される位相同期回路に、前記制御器に
よる分周比の制御に伴って前記基準周波数用発振器の周
波数を偏移させる回路を付設したことを特徴とする周波
数シンセサイザ。 2、周波数を偏移させる回路は、制御器から出力される
データを保持しかつ出力するデータ保持器と、このデー
タをデジタル変換するアナログ−デジタル変換器と、デ
ジタル信号の高周波を除去する低域ろ波器とで構成し、
この低域ろ波器の出力を前記基準周波数用発振器の周波
数制御端子に入力させるように構成してなる特許請求の
範囲第1項記載の周波数シンセサイザ。
[Claims] 1. A frequency synthesizer that generates a frequency in a required frequency band step at a required center frequency, which includes a reference frequency oscillator, a phase error detector, a loop filter, a voltage controlled oscillator, a frequency divider, and A phase locked circuit configured with a controller that changes and controls the frequency division ratio of a frequency divider is provided with a circuit that shifts the frequency of the reference frequency oscillator in accordance with the control of the frequency division ratio by the controller. A frequency synthesizer featuring: 2. The frequency shifting circuit consists of a data holder that holds and outputs the data output from the controller, an analog-to-digital converter that converts this data into digital data, and a low-frequency circuit that removes high frequencies from the digital signal. Consisting of a filter and
2. The frequency synthesizer according to claim 1, wherein the output of the low-pass filter is inputted to a frequency control terminal of the reference frequency oscillator.
JP1238641A 1989-09-14 1989-09-14 Frequency synthesizer Pending JPH03101418A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP1238641A JPH03101418A (en) 1989-09-14 1989-09-14 Frequency synthesizer

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1238641A JPH03101418A (en) 1989-09-14 1989-09-14 Frequency synthesizer

Publications (1)

Publication Number Publication Date
JPH03101418A true JPH03101418A (en) 1991-04-26

Family

ID=17033158

Family Applications (1)

Application Number Title Priority Date Filing Date
JP1238641A Pending JPH03101418A (en) 1989-09-14 1989-09-14 Frequency synthesizer

Country Status (1)

Country Link
JP (1) JPH03101418A (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63281521A (en) * 1987-05-14 1988-11-18 Japan Radio Co Ltd Frequency synthesizer

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63281521A (en) * 1987-05-14 1988-11-18 Japan Radio Co Ltd Frequency synthesizer

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