JPH021965Y2 - - Google Patents
Info
- Publication number
- JPH021965Y2 JPH021965Y2 JP13649982U JP13649982U JPH021965Y2 JP H021965 Y2 JPH021965 Y2 JP H021965Y2 JP 13649982 U JP13649982 U JP 13649982U JP 13649982 U JP13649982 U JP 13649982U JP H021965 Y2 JPH021965 Y2 JP H021965Y2
- Authority
- JP
- Japan
- Prior art keywords
- phase input
- capacitor
- positive
- signal
- operational amplifier
- 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.)
- Expired
Links
- 239000003990 capacitor Substances 0.000 claims description 15
- 238000006243 chemical reaction Methods 0.000 claims description 6
- 230000005236 sound signal Effects 0.000 claims description 5
- 238000001514 detection method Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 1
Landscapes
- Amplifiers (AREA)
- Networks Using Active Elements (AREA)
Description
【考案の詳細な説明】
本考案は、パルス位置変調、パルス幅変調など
のパルス時間変調信号をオーデイオ信号に変調す
る信号変換回路に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a signal conversion circuit that modulates a pulse time modulated signal such as pulse position modulation or pulse width modulation into an audio signal.
一般にパルス時間変調信号は、ローパスフイル
ターでベースバンドのみを取り出すことでオーデ
イオ信号に変換される。このような信号変換は、
第１図に示すようなFM波のパルスカウント検波
にその使用例を見ることができる。パルスカウン
ト検波は、FM波が一種の粗密波であることから
その性質を利用することによつて検波するもの
で、図に示すように、まず中間周波信号をリミツ
タ１にかけて方形波にし、ダイオードで負電圧だ
けを取り出して単安定マルチバイブレータ（単安
定マルチ）２のトリガ電圧とする。この単安定マ
ルチ２は、周波数に逆比例するパルス間隔をもつ
た互に逆相の２つのパルス列、すなわちパルス位
置変調信号を作り出す。このパルス位置変調信号
は、定電流源Ｉと共に差動回路３を構成している
トランジスタQ1，Q2のベースにそれぞれ加えら
れ、トランジスタQ1，Q2のコレクタに電流−電
圧変換された互に逆位相のパルス位置変調信号が
得られる。このパルス位置変調信号は、そのうち
の正相のものが演算増幅器A1の正相入力に、逆
相のものが逆相入力にそれぞれ入力され、そのキ
ヤリア成分が演算増幅器A1の正相及び逆相入力
間に接続しているコンデンサC1を通じて互に打
ち消され、このことにより演算増幅器A1の出力
にFM検波信号すなわちオーデイオ信号を得てい
る。 Generally, a pulse time modulated signal is converted into an audio signal by extracting only the baseband using a low-pass filter. This kind of signal conversion is
An example of its use can be seen in pulse count detection of FM waves as shown in Figure 1. Pulse count detection utilizes the properties of FM waves as they are a type of compressional wave to detect them.As shown in the figure, first the intermediate frequency signal is passed through limiter 1 to make it into a square wave, and then it is converted into a square wave using a diode. Only the negative voltage is taken out and used as the trigger voltage for the monostable multivibrator (monostable multi) 2. This monostable multi 2 produces two pulse trains of mutually opposite phases with a pulse interval inversely proportional to the frequency, ie, a pulse position modulation signal. This pulse position modulation signal is applied to the bases of transistors Q 1 and Q 2 that constitute the differential circuit 3 together with constant current source I, and is applied to the collectors of transistors Q 1 and Q 2 as a current-voltage converted signal. A pulse position modulation signal with an opposite phase is obtained. Of these pulse position modulation signals, the positive phase signal is input to the positive phase input of operational amplifier A 1 , and the negative phase signal is input to the negative phase input of operational amplifier A 1 . They cancel each other out through the capacitor C1 connected between the phase inputs, thereby obtaining an FM detection signal, that is, an audio signal, at the output of the operational amplifier A1 .
上記演算増幅器A1は、その出力と逆相入力と
の間に抵抗R1が、正相入力とアースとの間に抵
抗R2がそれぞれ接続されて差動増幅器として働
き、上記トランジスタQ1及びQ2のそれぞれのコ
レクタ抵抗R3及びR4の値が互いに等しく、かつ
R1＝R2とすることにより、出力の直流電圧は一
定値のOVになる。 The operational amplifier A1 functions as a differential amplifier with a resistor R1 connected between its output and the negative phase input, and a resistor R2 connected between the positive phase input and ground, and the transistors Q1 and The values of the respective collector resistances R 3 and R 4 of Q 2 are equal to each other and
By setting R 1 = R 2 , the output DC voltage becomes a constant value OV.
一般にパルス時間信号のキヤリア周波数はオー
デイオ信号に比べ十分に高いので、上記コンデン
サC1の値を適当な値に設定することにより、キ
ヤリア成分のみのキヤンセルを行うことができ
る。 Generally, the carrier frequency of a pulse time signal is sufficiently higher than that of an audio signal, so by setting the value of the capacitor C1 to an appropriate value, it is possible to cancel only the carrier component.
ところが、第１図の回路では、演算増幅器A1
の正相入力と逆相入力とがコンデンサC1を介し
て相互接続されているため、その出力信号の周波
数が高くなると、このコンデンサC1を介しての
正帰還が増大し、第２図に示すように高域周波数
においてピークを持つと共に、動作が不安定とな
る欠点があつた。 However, in the circuit shown in Figure 1, the operational amplifier A 1
Since the positive-phase input and the negative-phase input of the are interconnected through the capacitor C1 , as the frequency of its output signal increases, the positive feedback through this capacitor C1 increases, and as shown in Fig. 2. As shown, it has a peak at high frequencies and has the disadvantage of unstable operation.
本考案は上述した点に鑑みてなされたもので、
その目的とするところは、高域周波数特性の平坦
化と動作の安定化を図つた信号変換回路を提供す
ることにある。 This invention was made in view of the above points,
The purpose is to provide a signal conversion circuit that can flatten high-frequency characteristics and stabilize operation.
以下本考案を第３図及び第４図を参照して説明
するが、第３図において第１図と同等の部分には
同一符号を付してある。 The present invention will be described below with reference to FIGS. 3 and 4. In FIG. 3, the same parts as in FIG. 1 are designated by the same reference numerals.
本考案による信号変換回路では、演算増幅器
A1の正相入力をコンデンサC2を介してアースに
接続しているが、これ以外は第１図の回路と同じ
である。 In the signal conversion circuit according to the present invention, an operational amplifier
The positive phase input of A1 is connected to ground via capacitor C2 , but other than this the circuit is the same as the one shown in Figure 1.
このようにコンデンサC2を追加接続すると、
正相入力への正帰還量がコンデンサC1及びC2の
容量値に応じて減少する。すなわち、コンデンサ
C1のみの場合には全帰還となるが、コンデンサ
C2の付加によつて帰還量がC1／（C1＋C2）にな
る。従つて、正帰還量が制限されることになり、
動作が安定化すると共に、第４図に示すように、
周波数特性が高域まで平坦なものとなる。 If you additionally connect capacitor C 2 like this,
The amount of positive feedback to the positive phase input decreases according to the capacitance values of capacitors C1 and C2 . i.e. capacitor
If only C 1 is used, it will be full feedback, but if the capacitor
By adding C 2 , the amount of feedback becomes C 1 /(C 1 +C 2 ). Therefore, the amount of positive feedback is limited,
As the operation becomes more stable, as shown in Figure 4,
The frequency characteristics become flat up to the high range.
なお、上述の実施例では、コンデンサC1及び
C2と直列に抵抗が接続されていないが、小さな
値の抵抗であれば直列接続されても同様の効果が
得られる。 Note that in the above embodiment, the capacitors C 1 and
Although no resistor is connected in series with C 2 , the same effect can be obtained even if a small resistor is connected in series.
本考案は上述したように、キヤリアのキヤンセ
ルのため演算増幅器の正相入力と逆相入力との間
に接続したコンデンサによる正帰還効果がもたら
す高域ゲインの上昇、正相入力とアース間にコン
デンサを追加接続して帰還量を減少することでな
くしたものであり、このことにより動作の安定化
と周波数特性の平坦化の図られた信号変換回路が
得られる。 As mentioned above, this invention increases high-frequency gain due to the positive feedback effect caused by the capacitor connected between the positive-phase input and the negative-phase input of the operational amplifier to cancel the carrier, and the capacitor connected between the positive-phase input and the ground. This can be eliminated by additionally connecting the circuit to reduce the amount of feedback, thereby providing a signal conversion circuit with stable operation and flattened frequency characteristics.
第１図はFM波の検波に適用した従来回路を示
す回路、第２図は第１図の回路の欠点を説明する
ためのグラフ、第３図は本考案による回路の一実
施例を示す回路図、及び第４図は本考案の効果を
説明するためのグラフである。
A1……演算増幅器、C1，C2……コンデンサ、
R1，R2……抵抗。
Fig. 1 is a circuit showing a conventional circuit applied to detecting FM waves, Fig. 2 is a graph for explaining the drawbacks of the circuit shown in Fig. 1, and Fig. 3 is a circuit showing an embodiment of the circuit according to the present invention. 4 and 4 are graphs for explaining the effects of the present invention. A 1 ... operational amplifier, C 1 , C 2 ... capacitor,
R 1 , R 2 ...Resistance.
Claims (1)
に、逆相入力を抵抗を介してその出力にそれぞれ
接続すると共に、前記正相入力及び逆相入力間に
コンデンサを接続し、前記正相入力及び逆相入力
にそれぞれ加えられるパルス時間変調信号をオー
デイオ信号に変換する信号変換回路であつて、前
記演算増幅回路の正相入力をコンデンサを介して
アースに接続したことを特徴とする信号変換回
路。 The positive phase input of the operational amplifier is connected to the ground through a resistor, and the negative phase input is connected to the output thereof through a resistor, and a capacitor is connected between the positive phase input and the negative phase input, and the positive phase input and the negative phase input are connected to each other. 1. A signal conversion circuit for converting pulse time modulated signals applied to respective negative phase inputs into audio signals, characterized in that the positive phase input of the operational amplifier circuit is connected to ground via a capacitor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13649982U JPS5942641U (en) | 1982-09-10 | 1982-09-10 | signal conversion circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13649982U JPS5942641U (en) | 1982-09-10 | 1982-09-10 | signal conversion circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5942641U JPS5942641U (en) | 1984-03-19 |
| JPH021965Y2 true JPH021965Y2 (en) | 1990-01-18 |
Family
ID=30306888
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13649982U Granted JPS5942641U (en) | 1982-09-10 | 1982-09-10 | signal conversion circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5942641U (en) |
-
1982
- 1982-09-10 JP JP13649982U patent/JPS5942641U/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5942641U (en) | 1984-03-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPS6121007B2 (en) | ||
| US3999138A (en) | Detector for AM-FM signals | |
| JPH021965Y2 (en) | ||
| JPS5931048Y2 (en) | low noise amplifier | |
| JPS585594B2 (en) | rectifier circuit | |
| GB1575357A (en) | Quadrature type phase detectors | |
| JPS5930338B2 (en) | monostable multivibrator | |
| US4264867A (en) | Demodulator circuit for frequency-modulated signal | |
| JPH0246089Y2 (en) | ||
| JPH03286605A (en) | Optical receiver circuit | |
| US4027268A (en) | Demodulator for PM or FM signals | |
| JP2597340Y2 (en) | Limiter circuit | |
| JPS5936017Y2 (en) | high pass filter | |
| JPS596014Y2 (en) | AM receiver tuning signal generation circuit | |
| JPH0518707Y2 (en) | ||
| JPH0412464Y2 (en) | ||
| JPH0831745B2 (en) | Double balanced modulation circuit | |
| JPS6221091Y2 (en) | ||
| JPS6016113Y2 (en) | Tuning device using variable capacitance diode | |
| JP2518098Y2 (en) | DC cut circuit | |
| JPS6027445B2 (en) | Tuning meter circuit in pulse count type FM demodulation circuit | |
| JPH0240541Y2 (en) | ||
| JPS621418U (en) | ||
| JPS5837154Y2 (en) | FM signal receiving circuit | |
| JP2526776Y2 (en) | FM demodulation circuit |