JPS59110206A - Digital frequency synthesizer - Google Patents
Digital frequency synthesizerInfo
- Publication number
- JPS59110206A JPS59110206A JP21963582A JP21963582A JPS59110206A JP S59110206 A JPS59110206 A JP S59110206A JP 21963582 A JP21963582 A JP 21963582A JP 21963582 A JP21963582 A JP 21963582A JP S59110206 A JPS59110206 A JP S59110206A
- Authority
- JP
- Japan
- Prior art keywords
- frequency
- signal
- digital
- output
- supplied
- 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
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Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G5/00—Tone control or bandwidth control in amplifiers
Landscapes
- Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
Abstract
Description
【発明の詳細な説明】
この発明は設定した周波数をもつアナログ信号をデジタ
ル処理によシ発生するデジタル周波数合成器に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a digital frequency synthesizer that generates an analog signal having a set frequency by digital processing.
〈従来技術〉
従来のこの種のデジタル周波数合成器は、例えば特公昭
５６−２８０２号［デジタル周波数合成器」や特公昭５
４−４８２３号「周波数シンセサイザ」などにより知ら
れている。特公昭５６−２８０２号に示すものは第１図
に示すように周波数設定部１１に発生しようとする周波
数が設定されると、その周波数を示す信号が周波数デジ
タル信号として出力されて合成部１２へ供給される。合
成部１２では入力された周波数デジタル信号を累積加算
などを行って、設定周波数の正弦波をす・プリン）グし
、その各サンプル値をデジタル信号としたものと同一の
波形デジタル信号が合成される。この波形デジタル信号
はＤＡ変換器１３でアナログ信号１５に変換される。こ
のアナログ信号１５は周波数が前記設定周波数であシ、
かつその波形はステップ的に変化した階段状正弦波信号
である。このアナログ信号１５は低域通遍ろ波器１６に
ょ多階段波成分が除去されて正弦波信号１７が出力端子
１８に得られる。<Prior art> Conventional digital frequency synthesizers of this type are disclosed in, for example, Japanese Patent Publication No. 56-2802 [Digital Frequency Synthesizer] and Japanese Patent Publication No. 56-2802 [Digital Frequency Synthesizer].
It is known from No. 4-4823 "Frequency Synthesizer". In the system disclosed in Japanese Patent Publication No. 56-2802, when the frequency to be generated is set in the frequency setting section 11 as shown in FIG. Supplied. The synthesis unit 12 performs cumulative addition of the input frequency digital signals to generate a sine wave of a set frequency, and synthesizes a digital signal with the same waveform as that obtained by converting each sample value into a digital signal. Ru. This waveform digital signal is converted into an analog signal 15 by a DA converter 13. This analog signal 15 has a frequency equal to the set frequency,
Moreover, the waveform is a stepped sine wave signal that changes stepwise. The analog signal 15 is filtered by a low-pass filter 16 to remove multistep wave components, and a sine wave signal 17 is obtained at an output terminal 18.
特公昭５４−４８２３号に示すものは第２図に示すよう
に、周波数設定部１１より設定された周波数を示す周波
数デジタル信号が合成部１９に供給され、合成部１９で
はその周波数デジタル信号の累積加算彦どを行って波形
デジタル信号を出力する。As shown in FIG. 2, in the system disclosed in Japanese Patent Publication No. 54-4823, a frequency digital signal indicating a set frequency is supplied from a frequency setting section 11 to a synthesizing section 19, and the synthesizing section 19 accumulates the frequency digital signal. Performs addition and outputs a waveform digital signal.
この場合の波形デジタル信号は、設定周波数の三角波を
サンプリングし、その各サンプル値をデジタル信号に変
換したものと同一である。従って合成部１９からの波形
デジタル信号がＤＡ変換器１３へ供給され、その出力ア
ナログ信号２１は階段状三角波信号と々る。この階段状
三角波信号２１は波形変換部２２で正弦波信号２３に変
換され、正弦波信号２３は低域通過ろ波器１６で階段波
成分が除去されて出力端子１８に正弦波信号１７が得ら
れる。The waveform digital signal in this case is the same as that obtained by sampling a triangular wave of a set frequency and converting each sample value into a digital signal. Therefore, the waveform digital signal from the synthesis section 19 is supplied to the DA converter 13, and its output analog signal 21 is a stepped triangular wave signal. This stepped triangular wave signal 21 is converted into a sine wave signal 23 by a waveform converter 22, and the step wave component of the sine wave signal 23 is removed by a low pass filter 16, and a sine wave signal 17 is obtained at an output terminal 18. It will be done.
このように従来のデジタル周波数合成器においては、離
散的デジタル値である波形デジタル信号を作り、これを
連続的アナログ信号に変換するものであり、そのＤＡ変
換出力には階段波成分が存在し、この階段波成分を低域
通過ろ波器１６で除去していた。この低域通過涙波器１
６の遮断周波数ｆＱは階段波成分の周波数と、設定最大
周波数との中間の値に固定されていた。In this way, conventional digital frequency synthesizers create a waveform digital signal that is a discrete digital value and convert it into a continuous analog signal, and the DA conversion output has a staircase wave component. This staircase wave component was removed by a low pass filter 16. This low-pass tear wave device 1
The cutoff frequency fQ of No. 6 was fixed at a value intermediate between the frequency of the staircase wave component and the set maximum frequency.
この種のデジタル周波数合成器は出力信号の周波数精度
が高い点で優れている。しかし出力信号に含まれる歪成
分が比較的大きいことが判った。This type of digital frequency synthesizer is superior in that the frequency accuracy of the output signal is high. However, it was found that the distortion component contained in the output signal was relatively large.
特に第１図に示した周波数合成器においては、ＤＡ変換
器１３の出力は階段状正弦波であシ、これに含まれる周
波数成分はその正弦波の周波数成分、つまり設定周波数
と、階段波の周波数成分及びその高調波成分のみと考え
られ、従って低域沖波器１６で階段波成分を除去するこ
とにょシ、出力正弦波信号１７は歪が極めて小さいもの
が得られると考えられる。しかし実際には比較的大きな
歪が存在し、特に設定周波数が低く、これが低域通過Ｆ
波器１６の遮断周波数ｆｃより離れるに従って、出力正
弦波信号１７の歪が大きくなることが判明した。In particular, in the frequency synthesizer shown in Fig. 1, the output of the DA converter 13 is a stepped sine wave, and the frequency components included in this are the frequency components of the sine wave, that is, the set frequency and the stepped wave. It is considered that the output sine wave signal 17 contains only the frequency component and its harmonic component, and therefore, by removing the staircase wave component with the low-frequency wave transducer 16, an output sine wave signal 17 with extremely small distortion can be obtained. However, in reality, there is relatively large distortion, especially when the set frequency is low, and this is due to the low-pass F
It has been found that the distortion of the output sine wave signal 17 increases as the distance from the cutoff frequency fc of the wave generator 16 increases.
この問題を追求した結果、歪の存在は次の理由にもとす
くものであることが解明された。即ち、ＤＡ変換器１３
は必ずしもその変換特性が′正確には直線的でないだめ
、出力正弦波形が歪んだものとなる。また低域通過Ｆ波
器１６の遮断特性が急峻でないため、階段波成分が僅か
残り、この残った階段波成分が出力正弦波信号に与える
影響が、設定周波数、即ち出力正弦波信号周波数に応じ
て異なったものとなる。更に設定周波数を変換した時に
、出力信号にひげ状の雑音、いわゆるグリチが入り、こ
れが歪として検出される。As a result of pursuing this problem, it has been clarified that the existence of distortion can be attributed to the following reasons. That is, the DA converter 13
The conversion characteristics are not necessarily exactly linear, and the output sine waveform will be distorted. In addition, since the cut-off characteristic of the low-pass F wave filter 16 is not steep, only a small amount of the staircase wave component remains, and the influence of this remaining staircase wave component on the output sine wave signal depends on the set frequency, that is, the output sine wave signal frequency. It will be different. Furthermore, when the set frequency is converted, whisker-like noise, so-called glitch, is introduced into the output signal, and this is detected as distortion.
〈発明の概要〉
この発明の目的は設定周波数の値に拘らず歪が小さく、
かつ歪がはソ一定した出力が得られるデジタル周波数合
成器を提供することにある。<Summary of the Invention> The purpose of the present invention is to reduce distortion regardless of the set frequency value.
The object of the present invention is to provide a digital frequency synthesizer which can obtain an output with constant distortion.
この発明によれば、波形デジタル信号がＤＡ変換器でア
ナログ信号に変換された後に、可変ろ波器に供給される
。一方円波数デジタル信号は制御回路へ供給され、この
制御回路により、設定周波数に応じて可変泥波器の遮断
周波数が制御される。According to this invention, the waveform digital signal is converted into an analog signal by the DA converter and then supplied to the variable filter. On the other hand, the circular wave number digital signal is supplied to a control circuit, and this control circuit controls the cutoff frequency of the variable mud wave device according to the set frequency.
この結果、この遮断周波数は例えば設定周波数の第１次
高調波を除去するよう々値に常に制御され、出力正弦波
信号にその高調波成分が含まれず、かつ階段波成分に対
する減衰度が従来よりも大きくなり、歪が極めて小さい
、かつはソ一定値の出力信号が得られる。As a result, this cutoff frequency is always controlled to a value that removes, for example, the first harmonic of the set frequency, and the output sine wave signal does not include the harmonic component, and the degree of attenuation for the staircase wave component is lower than that of the conventional one. The output signal becomes large, and an output signal with extremely small distortion and a constant value of 0 is obtained.
〈実施例〉
第３図はこの発明の実施例を示し、周波数設定部１１か
らデジタル周波数合成部２４へ周波数デジタル信号が供
給される。周波数合成部２４は、第１図における合成部
１２及びＤＡ変換器１３よりなり、または第２図におけ
る合成部１９、ＤＡ変換器１３及び波形変換部２２から
々シ、設定周波数をもつ階段状正弦波信号１５又は２３
を出力する。<Embodiment> FIG. 3 shows an embodiment of the present invention, in which a frequency digital signal is supplied from the frequency setting section 11 to the digital frequency synthesis section 24. The frequency synthesizer 24 consists of the synthesizer 12 and the DA converter 13 in FIG. 1, or consists of the synthesizer 19, the DA converter 13, and the waveform converter 22 in FIG. wave signal 15 or 23
Output.
この発明においてはデジタル周波数合成部２４の出力は
遮断周波数を変化することができる可変戸波器２５へ供
給される。まだ周波数設定部１１の周波数デジタル信号
は制御回路２６へ供給され、制御回路２６は入力された
周波数デジタル信号から、制御信号を作シ、この制御信
号により可変ろ波器２５の遮断周波数を設定周波数よシ
高い近い値に制御する。In this invention, the output of the digital frequency synthesizer 24 is supplied to a variable wave filter 25 that can change the cut-off frequency. The frequency digital signal of the frequency setting section 11 is still supplied to the control circuit 26, and the control circuit 26 generates a control signal from the input frequency digital signal, and uses this control signal to set the cutoff frequency of the variable filter 25 to the set frequency. Control to a very high value.
可変ろ波器２５としては、例えば電圧制御低域通過Ｆ波
器を用い、この例として第４図に示すように伝達関数が
２次のアクティブローパスフィルタについて説明する。As the variable filter 25, for example, a voltage-controlled low-pass F-wave filter is used, and as an example, an active low-pass filter having a second-order transfer function as shown in FIG. 4 will be described.
入力端子２７は抵抗器２８．２９を通じて演算増幅器３
１の非反転入力側に接続され、この非反転入力側はコン
デンサ３２を通じて接地され、演算増幅器３１の反転入
力側及び出力側は互に接続され、その出力側はＦ波出力
端子３３に接続されると共に、コンデンサ３４を通じて
抵抗器２８．２９の接続点に接続される。The input terminal 27 is connected to the operational amplifier 3 through resistors 28 and 29.
1, this non-inverting input side is grounded through a capacitor 32, the inverting input side and the output side of the operational amplifier 31 are connected to each other, and the output side is connected to the F-wave output terminal 33. and is connected to the connection point of resistors 28 and 29 through capacitor 34.
このＦ波器の遮断周波数ｆｃは抵抗器２８．２９の各抵
抗値、コンデンサ３２．３４の各容量値により決定され
、かつこれら素子の値に反比例する。The cutoff frequency fc of this F-wave device is determined by the resistance values of the resistors 28 and 29 and the capacitance values of the capacitors 32 and 34, and is inversely proportional to the values of these elements.
この素子の値を変化するためこの例では抵抗器２８．２
９の一方をＣｄＳのような光導電素子で構成し、この光
導電素子を制御信号により制御する。In this example, resistor 28.2 is used to change the value of this element.
One of the photoconductive elements 9 is composed of a photoconductive element such as CdS, and this photoconductive element is controlled by a control signal.
第３図の制御回路２６においては、入力された周波数テ
ジタル信号はＤＡ変換部３５でアナログ信号に変換され
る。このアナログ信号は電圧制御部３６に供給されて、
電圧制御信号にされる。可変ろ波器２５として、先に述
べたようにその抵抗器の抵抗値を変化させることにより
遮断周波数ｆ’ｃを変化させ、しかもその抵抗値にｆｃ
が逆比例するものを用いる場合である。このため制御回
路２６においては設定周波数に比例した電圧を発生し、
かつその電圧に対しく可変戸波器２５の抵抗器の抵抗値
を逆比例して変化させる。このようにして設定周波数に
比例して遮断周波数ｆｃを制御することができる。In the control circuit 26 of FIG. 3, the input frequency digital signal is converted into an analog signal by the DA converter 35. This analog signal is supplied to the voltage control section 36,
It is made into a voltage control signal. As the variable filter 25, the cut-off frequency f'c is changed by changing the resistance value of the resistor as described above, and furthermore, the cutoff frequency f'c is changed by changing the resistance value of the resistor.
This is the case when using something that is inversely proportional. Therefore, the control circuit 26 generates a voltage proportional to the set frequency,
Moreover, the resistance value of the resistor of the variable door transducer 25 is changed in inverse proportion to the voltage. In this way, the cutoff frequency fc can be controlled in proportion to the set frequency.
このような制御を行う電圧制御部３６の例を第５図に示
す。即ち入力端子３７は抵抗器３８を通じて演算増幅器
３９の反転入力側に接続され、演算増幅器３９の反転入
力側は接地され、出力側はｐｎｐトランジスタ４１のベ
ースに接続される。FIG. 5 shows an example of the voltage control section 36 that performs such control. That is, the input terminal 37 is connected to the inverting input side of the operational amplifier 39 through the resistor 38, the inverting input side of the operational amplifier 39 is grounded, and the output side is connected to the base of the pnp transistor 41.
トランジスタ４１のエミッタは抵抗器４２を通じて電圧
子Ｖの電源端子４３に接続され、コレクタは発光ダイオ
ードのような発光素子４４を通じて電圧−■の電源端子
４５に接続される。発光素子４４よりの光を受光するＣ
ｄＳのような光導電素子４６の一端は電圧−ＶＢの電源
端子４７に接続され、他端は演算増幅器３９の反転入力
側に接続される。The emitter of the transistor 41 is connected to a power supply terminal 43 of a voltage element V through a resistor 42, and the collector is connected to a power supply terminal 45 of a voltage -■ through a light emitting element 44 such as a light emitting diode. C that receives light from the light emitting element 44
One end of a photoconductive element 46 such as dS is connected to a power supply terminal 47 at voltage -VB, and the other end is connected to the inverting input of an operational amplifier 39.
発光素子４４及び光導電素子４６はフォトカプラ４８を
構成している。The light emitting element 44 and the photoconductive element 46 constitute a photocoupler 48.
この構成において入力端子３７の入力電圧Ｖｒが増加す
ると、抵抗器３８を流れる電圧■Ｉも増加し、演算増幅
器３９の出力電圧は負方向に増加し、トランジスタ４１
のコレクタ電流、つまり発光素子４４の電流ＩＤが増加
する。フォトカップラの電流ＩＤ−抵抗Ｒ特性は第６図
に示すように電流ＩＤが増加すると抵抗Ｒは減少する。In this configuration, when the input voltage Vr of the input terminal 37 increases, the voltage I flowing through the resistor 38 also increases, the output voltage of the operational amplifier 39 increases in the negative direction, and the transistor 41
, that is, the current ID of the light emitting element 44 increases. As shown in FIG. 6, the current ID-resistance R characteristic of the photocoupler is such that as the current ID increases, the resistance R decreases.
よって発光素子４４からの光量も増加し、光導電素子４
６の抵抗値Ｒｃｌが減少し、この光導電素子４６を流れ
る電流ＩＰと、抵抗器３８を流れる電流Ｉｔとが等しく
なるように負帰還動作する。Therefore, the amount of light from the light emitting element 44 also increases, and the amount of light emitted from the photoconductive element 4 increases.
A negative feedback operation is performed so that the resistance value Rcl of the resistor 6 decreases, and the current IP flowing through the photoconductive element 46 and the current It flowing through the resistor 38 become equal.
演算増幅器３９の反転入力側は仮想接地と見なされ、そ
の電圧はゼロであシ、従って抵抗器３８の抵抗値をＲと
すると、■ＩキＶｒ／Ｒとなる。この電流Ｉｒは、演算
増幅器３９のバイアス電流と比較して充分大きく、電流
Ｉｒは光導電素子４６に大部分流れる。従ってＬｒ中Ｉ
Ｐである。これらより次式が成立する。The inverting input side of the operational amplifier 39 is regarded as a virtual ground, and its voltage is zero. Therefore, assuming that the resistance value of the resistor 38 is R, the result is 1Vr/R. This current Ir is sufficiently large compared to the bias current of the operational amplifier 39, and most of the current Ir flows through the photoconductive element 46. Therefore, I in Lr
It is P. From these, the following equation is established.
Ｖｆ 、 ＶＢ
Ｒ’ＲｃＩ
ＶＢ、Ｒは一定であるから、光導電素子４６の抵抗値Ｒ
ｃｌは入力電圧Ｖｘに逆比例した値となる。従って第４
図に示したアクティブフィルタの抵抗器２８．２９の一
方又は両方を光導電素子として、これに発光素子４４を
照射すると、入力電圧ｖｒ、つまり設定周差数に比例し
だ電、圧に逆比例して抵抗器２８．２９の一方又は両方
を制御することができる。従ってこの沖波器２５の遮断
周波数ｆｃは設定周波数に比例して変化する。Vf, VB R'RcI Since VB and R are constant, the resistance value R of the photoconductive element 46
cl has a value inversely proportional to the input voltage Vx. Therefore, the fourth
When one or both of the resistors 28 and 29 of the active filter shown in the figure is used as a photoconductive element and the light emitting element 44 is irradiated onto it, the input voltage vr, that is, the voltage is proportional to the set frequency difference and is inversely proportional to the pressure. can be used to control one or both of resistors 28,29. Therefore, the cutoff frequency fc of this wave wave device 25 changes in proportion to the set frequency.
フォトカブラ４８として第７図に示すように発光素子４
４と複数の光導電素子４６ 、２８ 、２９が一体にな
っているものを用い、その光導電素子２８．２９を第４
図のフィルタ２５の抵抗器２８．２９として使用するこ
とにより、制御特性を向上させることができる。即ちこ
のよう々フォトカプラにおいてはその複数の光導電素子
は同一基板に同時に形成され、同一特性をもっており、
周囲温度の変化にも影響されず正しい制御を行なうこと
ができる。As a photocoupler 48, the light emitting element 4 is
4 and a plurality of photoconductive elements 46, 28, 29 are integrated, and the photoconductive elements 28, 29 are
By using the resistors 28 and 29 of the filter 25 shown in the figure, the control characteristics can be improved. In other words, in such a photocoupler, the plurality of photoconductive elements are formed simultaneously on the same substrate and have the same characteristics.
Correct control can be performed without being affected by changes in ambient temperature.
上述においては可変ろ波器２５として２次アクティブロ
ーパスフィルタを用いたが、設定周波数のみを通過させ
る帯域通過可変ろ波器を用いてもよい。更にν波設数を
増加して高次のＦＷ器として構成することによシ減衰特
性を急峻なものとし、その複数のｐ波設の遮断周波数を
同時に制御するようにしてもよい。Ｐ波器２５の遮断周
波数の制御のために抵抗器として光導電素子を用いだが
、電界効果トランジスタを用いてもよい。Although a second-order active low-pass filter is used as the variable filter 25 in the above description, a band-pass variable filter that passes only a set frequency may also be used. Furthermore, the attenuation characteristic may be made steep by increasing the number of ν waves and configuring it as a high-order FW device, and the cutoff frequencies of the plurality of p waves may be controlled simultaneously. Although a photoconductive element is used as a resistor to control the cutoff frequency of the P-wave device 25, a field effect transistor may also be used.
く効 果〉
以上述べたようにこの発明によれば可変Ｆ波器２５の遮
断周波数を、設定周波数に比例して変化させているため
、デジタル周波数合成部２４の出力から、階段波成分の
みならず、出力正弦波信号の高調波成分、その他の雑音
成分も、設定周波数に拘らず一様に除去することができ
、従って歪が極めて小ない正弦波信号を得ることができ
る。しかも周波数精度が優れているという特徴は失なわ
れない。特に先の例に示したように、複合素子フォトカ
プラを用いると、ろ波器の遮断周波数制御が設定周波数
に正確に追従し、しかもダイナミックレンジが広く、歪
率特性もよい。Effects> As described above, according to the present invention, the cutoff frequency of the variable F wave generator 25 is changed in proportion to the set frequency, so that only the staircase wave component can be detected from the output of the digital frequency synthesizer 24. First, harmonic components and other noise components of the output sine wave signal can be uniformly removed regardless of the set frequency, and therefore a sine wave signal with extremely low distortion can be obtained. Moreover, the feature of excellent frequency accuracy is not lost. In particular, as shown in the previous example, when a composite element photocoupler is used, the cutoff frequency control of the filter accurately follows the set frequency, the dynamic range is wide, and the distortion rate characteristics are good.
【図面の簡単な説明】
第１図及び第２図はそれぞれ従来のデジタル周波数合成
器を示すブロック図、第３図はこの発明による周波数合
成器の一例を示すブロック図、第４図は可変Ｆ波器２５
の一例を示す接続図、第５図は電圧制御部３６の具体例
を示す接続図、第６図はフォトカプラの抵抗−電流特性
図、第７図は複合素子フォトカプラの一例を示す原理図
である。
１１：周波数設定部、１２，１９：合成部、１３．３５
：ＤＡ変換器、１８：出力端子、２４：デジタル周波数
合成部、２５：可変ろ波器、２６：制御回路。
特許出願人 東亜電波工業株式益社
代理人 草野□ 卓[BRIEF DESCRIPTION OF THE DRAWINGS] FIGS. 1 and 2 are block diagrams showing conventional digital frequency synthesizers, FIG. 3 is a block diagram showing an example of a frequency synthesizer according to the present invention, and FIG. 4 is a block diagram showing an example of a frequency synthesizer according to the present invention. wave device 25
A connection diagram showing an example, FIG. 5 is a connection diagram showing a specific example of the voltage control section 36, FIG. 6 is a resistance-current characteristic diagram of a photocoupler, and FIG. 7 is a principle diagram showing an example of a composite element photocoupler. It is. 11: Frequency setting section, 12, 19: Synthesizing section, 13.35
: DA converter, 18: Output terminal, 24: Digital frequency synthesizer, 25: Variable filter, 26: Control circuit. Patent applicant Taku Kusano, agent of Toa Denpa Kogyo Co., Ltd.
Claims (1)
生する周波数設定部と、その周波数デジタル信号が入力
され、設定された周波数の繰返し波形をもつ波形デジタ
ル信号を合成する合成部と、その波形デジタル信号をア
ナログ信号に変換するＤＡ変換器と、そのアナログ信号
が供給され、遮断周波数を変化することができる可変Ｐ
波器と、上記周波数デジタル信号が供給され、上記設定
周波数に応じて上記可変Ｐ波器の遮断周波数を制御する
制御回路とを具備するデジタル周波数合成器。(1) A frequency setting section that generates a frequency digital signal indicating a set frequency, a synthesizing section that receives the frequency digital signal and synthesizes a waveform digital signal having a repeating waveform of the set frequency, and the waveform digital signal. A DA converter that converts a signal into an analog signal, and a variable P to which the analog signal is supplied and whose cut-off frequency can be changed.
A digital frequency synthesizer comprising: a wave generator; and a control circuit to which the frequency digital signal is supplied and which controls a cutoff frequency of the variable P wave generator according to the set frequency.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21963582A JPS59110206A (en) | 1982-12-15 | 1982-12-15 | Digital frequency synthesizer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21963582A JPS59110206A (en) | 1982-12-15 | 1982-12-15 | Digital frequency synthesizer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS59110206A true JPS59110206A (en) | 1984-06-26 |
Family
ID=16738610
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21963582A Pending JPS59110206A (en) | 1982-12-15 | 1982-12-15 | Digital frequency synthesizer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59110206A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0311805A (en) * | 1989-06-09 | 1991-01-21 | Icom Inc | Frequency synthesizer |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4947308A (en) * | 1972-09-12 | 1974-05-08 | ||
| JPS5093764A (en) * | 1973-12-20 | 1975-07-26 | ||
| JPS5435744A (en) * | 1977-08-25 | 1979-03-16 | Ricoh Co Ltd | Safety device for fixing device |
-
1982
- 1982-12-15 JP JP21963582A patent/JPS59110206A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4947308A (en) * | 1972-09-12 | 1974-05-08 | ||
| JPS5093764A (en) * | 1973-12-20 | 1975-07-26 | ||
| JPS5435744A (en) * | 1977-08-25 | 1979-03-16 | Ricoh Co Ltd | Safety device for fixing device |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0311805A (en) * | 1989-06-09 | 1991-01-21 | Icom Inc | Frequency synthesizer |
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