JPS6031063A - Fm modulation meter - Google Patents
Fm modulation meterInfo
- Publication number
- JPS6031063A JPS6031063A JP13995883A JP13995883A JPS6031063A JP S6031063 A JPS6031063 A JP S6031063A JP 13995883 A JP13995883 A JP 13995883A JP 13995883 A JP13995883 A JP 13995883A JP S6031063 A JPS6031063 A JP S6031063A
- Authority
- JP
- Japan
- Prior art keywords
- frequency
- signal
- modulation
- converter
- voltage
- 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
Links
Abstract
Description
【発明の詳細な説明】
この発明は、たとえばビデオデツキの量産時に、ビデオ
デツキから出力されるＦＭ変調波の変調度を検査するの
に使用するＦＭ変調度計に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an FM modulation meter used for inspecting the modulation degree of an FM modulated wave output from a video deck, for example, during mass production of video decks.
ビデオデツキ等では、変調度を検査するのに、入力搬送
周波数５．００Ｍ１ｌｚで±５００ＫＨｚの周波数偏移
を読む必要がある。一般によく知られたＦＭ変調度の測
定方法としては、フォ〜スタシーレ検（１）
波器、レシオ検波器、複同調周波数弁別器等でＦＭ変調
波を検波し、その出力レベルを読む方法があるが、これ
らの検波器はコイルの調整が困難な上、周波数偏移の幅
が狭く、上記のようにとても±５００Ｋｌ（ｚまではと
れないという欠点がある。In a video deck or the like, in order to check the degree of modulation, it is necessary to read a frequency deviation of ±500 KHz at an input carrier frequency of 5.00 M11z. A generally well-known method for measuring the degree of FM modulation is to detect the FM modulation wave using a Foster Schiele detector (1) wave detector, ratio detector, double-tuned frequency discriminator, etc., and then read the output level. However, these detectors have the disadvantage that it is difficult to adjust the coil, the frequency deviation width is narrow, and as mentioned above, it is not possible to obtain up to ±500 Kl (z).
また他の測定方法としてはフォードラチャー検波器やス
ペクトルアナライザーを用いる方法があるが、フォード
ラチャー検波器はやはり周波数偏移の幅が狭いし、スペ
クトルアナライザーは周波数偏移は問題ないとしても、
波形を目視で読むのは、量産における測定検査には適し
ないという欠点があり、いずれにしても従来の測定方法
を用いたのでは、大なる周波数偏移のＦＭ変調波の変調
度を手軽に測定することができなかった。Another measurement method is to use a Fordracher detector or a spectrum analyzer, but the Fordracher detector still has a narrow frequency deviation width, and the spectrum analyzer has no problem with frequency deviation.
Visually reading the waveform has the disadvantage that it is not suitable for measurement inspection in mass production, and in any case, using conventional measurement methods, it is easy to measure the modulation degree of FM modulated waves with large frequency deviations. could not be measured.
それゆえに、この発明の目的は、周波数偏移が大なるＦ
Ｍ変調波の測定が可能であり、量産時の使用に適したＦ
Ｍ変調度計を提供することである。Therefore, an object of the present invention is to
It is possible to measure M modulated waves and is suitable for use in mass production.
An object of the present invention is to provide an M modulation depth meter.
上記目的を達成するために、この発明のＦＭ変調度計は
、ＦＭ変調波発生源よりのＦＭ変調波と内部発振器より
の信号とを受けて前記ＦＭ変調波（２）
を周波数変換する周波数変換器と、周波数変換されたＦ
Ｍ変調波信号を受け周波数を電圧に変換する周波数−電
圧変換器と、この周波数−電圧変換器の出力のうち低周
波成分のみを通過させるローパスフィルタと、このロー
パスフィルタ出力を表示するレベル表示器とから構成さ
れている。In order to achieve the above object, the FM modulation degree meter of the present invention receives an FM modulated wave from an FM modulated wave generation source and a signal from an internal oscillator, and converts the frequency of the FM modulated wave (2). and the frequency-converted F
A frequency-voltage converter that receives an M-modulated wave signal and converts the frequency into a voltage, a low-pass filter that passes only low-frequency components of the output of this frequency-voltage converter, and a level indicator that displays the output of this low-pass filter. It is composed of.
以下、図面に示す実施例により、この発明をさらに詳細
に説明する。図面において、１はＦＭ変調波源である。Hereinafter, the present invention will be explained in more detail with reference to embodiments shown in the drawings. In the drawing, 1 is an FM modulated wave source.
このＦＭ変調波源１は搬送波５．５Ｍ ｆｉｚ、周波数
偏移５００ＫＩＩｚ、音声帯域信号ＩＫｔｌｚのＦＭ変
調波信号を出力する。２は、ＦＭ変変調波源上り出力さ
れるＦＭ変調波信号を受けて、その変調度を測定するた
めのＦＭ変調度計である。This FM modulated wave source 1 outputs an FM modulated wave signal having a carrier wave of 5.5 M fiz, a frequency shift of 500 KIIz, and a voice band signal IKtlz. Reference numeral 2 denotes an FM modulation degree meter for receiving an FM modulation wave signal outputted upstream from the FM modulation wave source and measuring its modulation degree.
ＦＭ変調度計２は、ＦＭ変調波源１と内部の５Ｍ Ｈｚ
発振器４よりの信号を受ける周波数変換器３、前記５Ｍ
Ｉ（ｚ発振器４、周波数変換器３の出力端に接続される
１／１０分周器５、この１／１０分周器５の出力端に接
続される周波数−電圧変換器６、この周波数−電圧変換
器６の出力端に接続されるローパスフィルタ７及び、こ
のローパスフィルタ７（３）
の音声帯域信号出力のレベルを表示する出力レベル表示
器８とから構成されている。The FM modulation depth meter 2 is connected to the FM modulation wave source 1 and the internal 5MHz
A frequency converter 3 receiving a signal from an oscillator 4, the 5M
I(z oscillator 4, 1/10 frequency divider 5 connected to the output terminal of the frequency converter 3, frequency-voltage converter 6 connected to the output terminal of this 1/10 frequency divider 5, this frequency - It consists of a low-pass filter 7 connected to the output end of the voltage converter 6, and an output level display 8 that displays the level of the audio band signal output of the low-pass filter 7(3).
上記実施例ＦＭ変調度計２において、ＦＭ変調波源１よ
り、５．５ＭＨｚのＦＭ変調波が入力されると、周波数
変換器３は、５ＭＨｚ発振器４よりの５ＭＨｚ信号との
差の周波数５００ＫＨｚの信号に変換する。この５００
ＫＨｚの信号は、１／１０分周器５でさらに５０ＫＨｚ
の信号に分周され、周波数−電圧変換器６に入力される
。ここで使用される周波数−電圧変換器６はフルスケー
ル１００ＫＩＩｚ程度のものであり、直線性の良い所で
周波数信号が電圧信号に変換される。この電圧信号は、
さらにローパスフィルタフにかけられ、その出力には、
変調成分、すなわち音声帯域信号が導出される。この音
声帯域信号の出力レベルをレベル表示器８に表示するこ
とにより、ＦＭ変調波源１より出力されるＦＭ変調波の
変調度を測定することができる。In the above embodiment FM modulation degree meter 2, when a 5.5 MHz FM modulated wave is input from the FM modulated wave source 1, the frequency converter 3 converts the 5.5 MHz signal from the 5 MHz oscillator 4 into a signal with a frequency of 500 KHz, which is the difference between the 5 MHz signal and the 5 MHz signal from the 5 MHz oscillator 4. Convert to This 500
The KHz signal is further divided into 50KHz by 1/10 frequency divider 5.
The signal is frequency-divided into a signal and input to the frequency-voltage converter 6. The frequency-voltage converter 6 used here has a full scale of about 100 KIIz, and the frequency signal is converted into a voltage signal at a location with good linearity. This voltage signal is
It is further passed through a low-pass filter, and the output is
A modulation component, ie a voice band signal, is derived. By displaying the output level of this audio band signal on the level display 8, the degree of modulation of the FM modulated wave output from the FM modulated wave source 1 can be measured.
なお、上記実施例において、周波数−電圧変換器６とし
てフルスケール１００ＫＩｌｚの安価なものを使用して
いるため、周波数変換器３の出力端に（４）
１／１０分周器５を設けているが、周波数−電圧変換器
のフルスケール幅が大なるものを使用することにより、
分周器は省略することが可能である。In the above embodiment, since an inexpensive one with a full scale of 100 KIlz is used as the frequency-voltage converter 6, a 1/10 frequency divider 5 (4) is provided at the output end of the frequency converter 3. However, by using a frequency-voltage converter with a large full-scale width,
The frequency divider can be omitted.
以上のようにこの発明のＦＭ変調度計によれば、周波数
変換したＦＭ変調波を周波数−電圧変換器に加え、その
出力をローパスフィルタにかけて変調成分を取出し、そ
のレベルを読み、変調度を測定するものであるから、比
較的広い周波数偏移のものでも迅速容易に、しかも精度
良く測定できるので、量産用のＦＭ変調度計として好適
である。As described above, according to the FM modulation degree meter of the present invention, the frequency-converted FM modulated wave is applied to a frequency-voltage converter, the output is filtered through a low-pass filter, the modulation component is extracted, the level is read, and the modulation degree is measured. Because of this, even relatively wide frequency deviations can be measured quickly, easily, and with high precision, making it suitable as a mass-produced FM modulation meter.
図面はこの発明の１実施例を示すＦＭ変調度計のブロッ
ク図である。
１７ＦＭ変調波源、２ ： ＦＭ変調度計、３：周波数
変換器、４ ： ５ Ｍｌｌｚ発振器、５ ：１ ／１
０分周器、６：周波数−電圧変換器７：ローパスフィル
タ、８：出力レベル表示器特許出願人 ローム株式会社
代理人 弁理士 中 村 茂 信
（５）
ｌ（The drawing is a block diagram of an FM modulation meter showing one embodiment of the present invention. 17 FM modulation wave source, 2: FM modulation depth meter, 3: frequency converter, 4: 5 Mllz oscillator, 5: 1/1
0 frequency divider, 6: Frequency-voltage converter 7: Low-pass filter, 8: Output level indicator Patent applicant: ROHM Co., Ltd. Agent, Patent attorney: Shigeru Nakamura (5) l(
Claims (1)
よりの信号とを受けて前記ＦＭ変調波を周波数変換する
周波数変換器と、周波数変換されたＦＭ変調波信号を受
け周波数を電圧に変換する周波数−電圧変換器と、この
周波数−電圧変換器の出力のうち低周波成分のみを通過
させるローパスフィルタと、このローパスフィルタ出力
を表示するレベル表示器とからなるＦＭ変調度計。(1) A frequency converter that receives an FM modulated wave from an FM modulated wave generation source and a signal from an internal oscillator and converts the frequency of the FM modulated wave, and a frequency converter that receives the frequency-converted FM modulated wave signal and converts the frequency into a voltage. An FM modulation meter comprising a frequency-to-voltage converter, a low-pass filter for passing only low-frequency components of the output of the frequency-to-voltage converter, and a level indicator for displaying the output of the low-pass filter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13995883A JPS6031063A (en) | 1983-07-30 | 1983-07-30 | Fm modulation meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13995883A JPS6031063A (en) | 1983-07-30 | 1983-07-30 | Fm modulation meter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6031063A true JPS6031063A (en) | 1985-02-16 |
Family
ID=15257627
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13995883A Pending JPS6031063A (en) | 1983-07-30 | 1983-07-30 | Fm modulation meter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6031063A (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4947706A (en) * | 1972-05-12 | 1974-05-09 |
-
1983
- 1983-07-30 JP JP13995883A patent/JPS6031063A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4947706A (en) * | 1972-05-12 | 1974-05-09 |
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