JPH0314812Y2 - - Google Patents
Info
- Publication number
- JPH0314812Y2 JPH0314812Y2 JP1284384U JP1284384U JPH0314812Y2 JP H0314812 Y2 JPH0314812 Y2 JP H0314812Y2 JP 1284384 U JP1284384 U JP 1284384U JP 1284384 U JP1284384 U JP 1284384U JP H0314812 Y2 JPH0314812 Y2 JP H0314812Y2
- Authority
- JP
- Japan
- Prior art keywords
- frequency
- circuit
- modulated wave
- signal
- division ratio
- 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
- 238000003079 width control Methods 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 4
- 230000006866 deterioration Effects 0.000 description 2
- 230000005236 sound signal Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
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- Transmitters (AREA)
Description
【考案の詳細な説明】
本考案はFM変調波の復調信号レベルの制御回
路に係り、FM変調波を任意の分周比（１／Ｎ）
にて分周を行い、FM変調波の周波数偏移巾を可
変し、この分周出力と周波数0（１−１／Ｎ）と
をミキサにて混合する構成とする事により、簡
易、安価でＳ／Ｎの良い音質の良好なFM変調波
の偏移巾制御回路を提供する事を目的とする。[Detailed description of the invention] This invention relates to a control circuit for the demodulated signal level of an FM modulated wave, and the FM modulated wave is divided at an arbitrary frequency division ratio (1/N).
By dividing the frequency at , varying the frequency shift width of the FM modulated wave, and mixing the divided output and frequency 0 (1-1/N) at a mixer, it is simple and inexpensive. The purpose of the present invention is to provide a shift width control circuit for FM modulated waves with good S/N and good sound quality.
テレビジヨン電波の音量制御或いはCATV放
送を受信してテレビジヨン受像機で受像できる様
に受信信号の周波変換、選局及び、デイスクラン
ブル等の機能を有するセツトトツプにおける音量
制御は、一旦FM変調波の復調を行い、その復調
信号のレベルコントロールを行い、レベルコント
ロールされた復調信号を再度FM変調を行つて、
テレビ電波として送出し、又は前記セツトトツプ
の場合は、その出力をRF信号に変換してテレビ
ジヨン受像機へ供給している。 The volume control in the set top, which has functions such as frequency conversion, tuning, and descrambling of the received signal so that it can receive the volume control of television radio waves or CATV broadcasting and receive it on the television receiver, is performed once by adjusting the FM modulation wave. Perform demodulation, control the level of the demodulated signal, perform FM modulation on the level-controlled demodulated signal again,
It is sent out as television radio waves, or in the case of the set top, its output is converted into an RF signal and supplied to a television receiver.
この具体的な回路ブロツク図の従来例を第１図
に示す。１はFM変調波の入力端子、２は復調回
路でその出力はオーデイオ信号が出力され、それ
はレベルコントロール回路３へ供給され、ここで
制御装置４によりそのレベルがコントロールされ
る。コントロールされたオーデイオ信号は、変調
回路５へ供給され、ここで更にFM変調され、音
声のレベルコントロールされたFM変調信号とし
て出力される。 A conventional example of this specific circuit block diagram is shown in FIG. 1 is an input terminal for an FM modulated wave, and 2 is a demodulation circuit from which an audio signal is output, which is supplied to a level control circuit 3, where its level is controlled by a control device 4. The controlled audio signal is supplied to the modulation circuit 5, where it is further FM modulated and output as an FM modulated signal with audio level control.
上記従来のFM変調波信号のレベルコントロー
ル方式の欠点は、部品点数が多く回路の複雑な復
調回路２及び変調回路５を必要とする事である。 The drawback of the conventional level control system for the FM modulated wave signal is that it requires a demodulation circuit 2 and a modulation circuit 5 which have a large number of parts and are complex circuits.
これらの複雑な回路を必要とする為、いきおい
装置が大型化し、高価になるという欠点を有して
いた。又、他の大きな欠点として復調回路及び変
調回路というＳ／Ｎの悪化し易い回路を有してい
る為、音質が劣化するという大きな欠点を有して
いた。 Since these complicated circuits are required, the ikioi device has the disadvantage of becoming large and expensive. Another major drawback is that the sound quality deteriorates because it includes a demodulation circuit and a modulation circuit, which are susceptible to deterioration in S/N ratio.
本考案は係る従来の問題点に鑑み、少ない構成
部品で安価なレベル制御回路を実現し、且つＳ／
Ｎ劣化のない音質の良好なFM変調波のレベル制
御回路を実現するもので、以下第２図に示す本考
案の一実施例になるブロツク図について説明す
る。第１図と同一部分には同一符号を付して説明
する。７は分周器、８はミキサ回路を示す。 In view of these conventional problems, the present invention realizes an inexpensive level control circuit with a small number of components, and also has S/
A block diagram of an embodiment of the present invention shown in FIG. 2, which realizes a level control circuit for FM modulated waves with good sound quality and no N deterioration, will be described below. The same parts as in FIG. 1 will be described with the same reference numerals. 7 is a frequency divider, and 8 is a mixer circuit.
９は電圧制御発振器（以下VCOという）、１０
はローパスフイルタ（以下LPFという）、１１は
位相比較器、１２はプリスケラで、これらにより
PLL回路を構成している。１３はプログラマブ
ル分周器であり、中に発振器を内蔵している。１
４はマイコンを夫々示す。 9 is a voltage controlled oscillator (hereinafter referred to as VCO), 10
is a low-pass filter (hereinafter referred to as LPF), 11 is a phase comparator, and 12 is a prescaler.
It constitutes a PLL circuit. 13 is a programmable frequency divider, which has an oscillator built therein. 1
4 indicates a microcomputer.
次に、これらの回路動作について説明する。入
力端子１に入来したFM変調波信号は分周器７で
分周比１／Ｎに分周される。この分周比１／Ｎ
は、外部制御装置４（ボリユーム等）により人為
的に制御され、マイコン１４により任意の分周比
１／Ｎが設定され、FM変調波のキヤリア（搬送
波周波数）0及びその周波数偏移巾は１／Ｎに分
周される。この周波数偏移巾が任意に分周される
事により、これを復調した音声レベルも分周比
１／Ｎに対応して変化する事になり、音量がこれ
により制御される。一方前述の如く分周器７によ
る分周により、周波数偏移巾のみならずキヤリア
0迄も分周される事になる。そこで分周されたキ
ヤリア0／Ｎを元の0に戻す必要がある。 Next, the operation of these circuits will be explained. The frequency of the FM modulated wave signal input to the input terminal 1 is divided by the frequency divider 7 to a frequency division ratio of 1/N. This frequency division ratio 1/N
is artificially controlled by an external control device 4 (volume, etc.), an arbitrary frequency division ratio of 1/N is set by the microcomputer 14, and the carrier (carrier frequency) of the FM modulated wave is 0 and its frequency deviation width is 1. /N. By arbitrarily dividing this frequency shift width, the audio level demodulated from it also changes in accordance with the frequency division ratio of 1/N, and the volume is thereby controlled. On the other hand, as mentioned above, by dividing the frequency by the frequency divider 7, not only the frequency deviation width but also the carrier
The frequency will also be divided up to 0 . Therefore, it is necessary to return the frequency-divided carrier 0 /N to the original 0 .
その回路が符合８〜１３で示す回路で構成され
ている。プログラマブル分周器１３では内蔵され
ている発振器の周波数の分周を行つており、位相
比較器１１、LPF１０、VCO９を介して、ミキ
サ回路８にその周波数を供給している。このミキ
サ回路８へVCO９から供給される周波数〓vco、
〓vco＝0（１−１／Ｎ）… (1)
である。0／Ｎと〓vcoが供給されるミキサ回路
８で発生する信号の内、
0／Ｎ＋0（１−１／Ｎ）＝0… (2)
(2)式で表わされる0のみがミキサ回路８から取出
され、端子６より出力される。 The circuit is composed of circuits indicated by numerals 8 to 13. The programmable frequency divider 13 divides the frequency of a built-in oscillator, and supplies the frequency to the mixer circuit 8 via the phase comparator 11, LPF 10, and VCO 9. The frequency supplied from the VCO 9 to the mixer circuit 8 is 〓vco, 〓vco= 0 (1-1/N)... (1). Among the signals generated in the mixer circuit 8 to which 0 /N and 〓vco are supplied, 0 /N+ 0 (1-1/N) = 0 ... (2) Only 0 expressed by equation (2) is generated in the mixer circuit 8. The signal is taken out from the terminal 6 and outputted from the terminal 6.
上記の周波数関係になる様に、プログラマブル
分周器１３及び分周器７の分周比がマイコン１４
により制御される。 The frequency division ratio of the programmable frequency divider 13 and the frequency divider 7 is adjusted to the microcomputer 14 so that the above frequency relationship is achieved.
controlled by
上述の如くFM変調波のレベル制御回路では従
来の如く、多数の部品を必要とし、複雑な回路と
なる復調回路及び変調回路を有しておらず、これ
に換えてICで構成される（符号９〜１４）部品
となる為、回路が極めて簡易となるものである。 As mentioned above, the FM modulated wave level control circuit does not have a demodulation circuit and a modulation circuit, which are complicated circuits and require a large number of components as in the past. 9 to 14) Since it is a component, the circuit is extremely simple.
更に又大きな特徴として、Ｓ／Ｎの劣化する復
調回路及び変調回路を有していない為、音質の良
好な音量制御回路とする事ができるものである。 Another major feature is that since it does not have a demodulation circuit or a modulation circuit that degrades the S/N ratio, it can be used as a volume control circuit with good sound quality.
第１図は従来のFM変調波のレベル制御回路の
ブロツク図、第２図は本考案の一実施例になる
FM変調波のレベル制御回路のブロツク図を夫々
示す。
４……制御回路（音量）、７……分周器、８…
…ミキサ回路、９……電圧制御発振器（VCO）、
１０……ローパスフイルタ（LPF）、１１……位
相比較回路、１２……プリスケラー、１３……プ
ログラマブル分周器、１４……マイコン。
Figure 1 is a block diagram of a conventional FM modulated wave level control circuit, and Figure 2 is an example of the present invention.
The block diagrams of the level control circuits for FM modulated waves are shown. 4... Control circuit (volume), 7... Frequency divider, 8...
...Mixer circuit, 9...Voltage controlled oscillator (VCO),
10...Low pass filter (LPF), 11...Phase comparison circuit, 12...Prescaler, 13...Programmable frequency divider, 14...Microcomputer.
Claims (1)
比１／Ｎに分周する分周器と、この分周器の出力
信号と0（１−１／Ｎ）の周波数の信号とを混合
するミキサ回路とからなり、該分周比１／Ｎを可
変する事により、該分周器で該周波数被変調波の
偏移巾を可変して、該周波数被変調波の復調信号
のレベルを可変する様にした事を特徴とするFM
変調波の偏移巾制御回路。 A frequency divider that divides a frequency modulated wave having a carrier frequency of 0 to a frequency division ratio of 1/N, and a mixer that mixes the output signal of this frequency divider and a signal with a frequency of 0 (1-1/N). By varying the frequency division ratio 1/N, the shift width of the frequency modulated wave is varied by the frequency divider, and the level of the demodulated signal of the frequency modulated wave is varied. FM characterized by
Modulated wave deviation width control circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1284384U JPS60127017U (en) | 1984-01-31 | 1984-01-31 | FM modulated wave deviation width control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1284384U JPS60127017U (en) | 1984-01-31 | 1984-01-31 | FM modulated wave deviation width control circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60127017U JPS60127017U (en) | 1985-08-27 |
| JPH0314812Y2 true JPH0314812Y2 (en) | 1991-04-02 |
Family
ID=30496290
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1284384U Granted JPS60127017U (en) | 1984-01-31 | 1984-01-31 | FM modulated wave deviation width control circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60127017U (en) |
-
1984
- 1984-01-31 JP JP1284384U patent/JPS60127017U/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60127017U (en) | 1985-08-27 |
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