JPS59122238A - Fm receiver - Google Patents
Fm receiverInfo
- Publication number
- JPS59122238A JPS59122238A JP23104582A JP23104582A JPS59122238A JP S59122238 A JPS59122238 A JP S59122238A JP 23104582 A JP23104582 A JP 23104582A JP 23104582 A JP23104582 A JP 23104582A JP S59122238 A JPS59122238 A JP S59122238A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- pilot
- power supply
- frequency
- filter
- 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.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B15/00—Suppression or limitation of noise or interference
- H04B15/02—Reducing interference from electric apparatus by means located at or near the interfering apparatus
- H04B15/04—Reducing interference from electric apparatus by means located at or near the interfering apparatus the interference being caused by substantially sinusoidal oscillations, e.g. in a receiver or in a tape-recorder
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
- H04B1/1018—Means associated with receiver for limiting or suppressing noise or interference noise filters connected between the power supply and the receiver
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Circuits Of Receivers In General (AREA)
Abstract
Description
【発明の詳細な説明】
本発明はＦＭ方式によって多重化電話信号を伝送するシ
ステムに用いる受信装置、さらに詳しく云えば監視制御
信号等のサービス信号を′硫話信号の下側周波数帯を利
用して伝送するシステムに用いるＦＭ受信装置に関する
。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a receiving device used in a system that transmits multiplexed telephone signals using the FM method, and more specifically, to transmit service signals such as supervisory control signals by utilizing the lower frequency band of the telephone signal. The present invention relates to an FM receiving device used in a transmission system.
従来、この種のＦＭ回線においては、伝送信号のレベル
を監視するために信号の近傍周波数を用いてパイロット
信号を伝送する方法が用いられており、受信装置にはパ
イロット信号を検出するパイロット検出器が備えられて
いた。Conventionally, in this type of FM line, a method has been used in which a pilot signal is transmitted using a frequency near the signal in order to monitor the level of the transmission signal, and the receiving device is equipped with a pilot detector to detect the pilot signal. was provided.
第１図はそのＦＭ受信装置の一例を示す図である。端子
１から入力した搬送周波数信号ハミキサ２において局部
発振器３から得た局発信号と混合され、中間周波数信号
に変換されたのち、中間周波数フィルタ４、リミッタ増
幅器５を経てＦＭ復調器６でベースバンド信号に復調さ
れ、ベースバンド増幅器７によって増幅される。FIG. 1 is a diagram showing an example of the FM receiving device. The carrier frequency signal input from terminal 1 is mixed with the local oscillator signal obtained from local oscillator 3 at mixer 2 and converted to an intermediate frequency signal, and then passed through intermediate frequency filter 4 and limiter amplifier 5 to baseband signal at FM demodulator 6. The signal is demodulated and amplified by the baseband amplifier 7.
ベースバンド信号に含１れるパイロット信号に阻止フィ
ルタ１０によって反射され、パイロット検出器８に導か
れ、そのレベルが検出されて端子９より送り出される。The pilot signal included in the baseband signal is reflected by the rejection filter 10 and guided to the pilot detector 8, where its level is detected and sent out from the terminal 9.
搬送周波数信号がＦＭ信号としての最低正常レベル（以
後スケルチレベルと称する）以上の場合、スイッチ１１
ハ閉じており、ベースバンド信号は端子１２よシ送出さ
れる。ところがスケルチレベル以下の場合はスイッチ１
１ば開となっているので、ＦＭ雑音は端子１２から出力
されない。When the carrier frequency signal is higher than the lowest normal level (hereinafter referred to as squelch level) as an FM signal, the switch 11
The baseband signal is sent out through the terminal 12. However, if the squelch level is below, switch 1
Since the terminal 12 is open, no FM noise is output from the terminal 12.
一方、パイロット信号は、搬送周波数信号がスケルチレ
ベル以上の場合他に故障が無い限りパイロット検出器８
によって正常に存在すると検出されるが、スケルチレベ
ルよりわずかに低下するとＦＭ復調器６の動作によって
パイロット信号レベルが小となり、パイロット検出器８
によって存在しないと判断される。ところが端子１にお
ける搬送周波数信号がスケルチレベルより大きく低下す
ると、ＦＭ復調器６の出力のＦＭ雑音が急激に増加し、
パイロット検出器８に含壕れるフィルタ内にこのＦＭ雑
音が漏洩して検波され、あたかもパイロット信号が正常
に存在するように誤判断される。ただし、この場合は搬
送周波数信号の入力がスケルチレベル以下になった時点
でスイッチ１１は開となっているので端子１２からは何
等の雑音も出力されることはない。On the other hand, if the carrier frequency signal is above the squelch level, the pilot signal is detected by the pilot detector 8 as long as there is no other failure.
However, if it drops slightly below the squelch level, the pilot signal level becomes small due to the operation of the FM demodulator 6, and the pilot signal level is detected as being normally present by the pilot detector 8.
It is determined that it does not exist. However, when the carrier frequency signal at terminal 1 drops significantly below the squelch level, the FM noise at the output of FM demodulator 6 suddenly increases.
This FM noise leaks into the filter included in the pilot detector 8 and is detected, making it erroneously determined that the pilot signal exists normally. However, in this case, since the switch 11 is open when the input of the carrier frequency signal becomes below the squelch level, no noise is output from the terminal 12.
さて、スケルチレベル以下になった搬送周波数信号の入
力レベルは一般には一定ではなく、常時変動するため、
レベルによっては前述のようにパイロット信号が存在し
ないと判断したり、また充分に低くなって存在すると誤
判断したシする動作を繰り返す状態が生じる。その結果
、パイロット検出器８に含１れるトランジスタ等がオン
・オフを繰り返し、その繰シ返し周波数が多重電話信号
の下側周波数帯、すなわちサービス信号の周波数帯に一
致してしまい悪影響を及ぼす。Now, since the input level of the carrier frequency signal that has fallen below the squelch level is generally not constant and constantly fluctuates,
Depending on the level, as described above, a state may occur in which the pilot signal is determined not to exist, or the pilot signal is sufficiently low to be erroneously determined to be present. As a result, the transistors included in the pilot detector 8 are repeatedly turned on and off, and the repetition frequency matches the lower frequency band of the multiplex telephone signal, that is, the frequency band of the service signal, resulting in an adverse effect.
第２図は第１図に示した従来のＦＭ受信装置の一部詳細
図である。ベースバンド増幅器７とパイロット検出器８
Ｖｉ共通の直流電源に接続される電源線１３で接続され
ている。ここでは説″明の便宜のためベースバンド増幅
器７を例にとって示したが、他の回路２〜１１にも共通
電源が使用されている場合もある。そのため前記繰υ返
し周波数は電源線１３を介してベースバンド増幅器７、
あるいは他の回路に漏洩する。FIG. 2 is a partially detailed diagram of the conventional FM receiver shown in FIG. Baseband amplifier 7 and pilot detector 8
They are connected by a power line 13 that is connected to a common DC power source. Here, for convenience of explanation, the baseband amplifier 7 is shown as an example, but the other circuits 2 to 11 may also use a common power supply. via a baseband amplifier 7,
Or it leaks to other circuits.
第３図はＦＭ受信装置における使用周波数帯を示した図
で、１４が多重電話信号、１５がパイロット信号、１６
が多重電話信号１４の下側帯を用いて伝送される監視制
御信号等のサービス信号である。前記繰シ返し周波数は
、サービス信号１６の周波数帯に一致してしまい、サー
ビス信号に対して多大の雑音を与える。Figure 3 is a diagram showing the frequency bands used in the FM receiver, where 14 is a multiplex telephone signal, 15 is a pilot signal, and 16 is a diagram showing the frequency bands used in the FM receiver.
is a service signal such as a supervisory control signal transmitted using the lower band of the multiplex telephone signal 14. The repetition frequency coincides with the frequency band of the service signal 16 and causes a large amount of noise to the service signal.
本発明の目的は上記パイロット検出器がオン・オフを繰
り返しても、サービス信号に雑音を与えることのないＦ
Ｍ受信装置を提供することにある。An object of the present invention is to provide an F-F that does not add noise to the service signal even when the pilot detector is repeatedly turned on and off.
An object of the present invention is to provide an M receiving device.
前記目的を達成するために本発明によるＦＭ受信装置は
ＦＭによって伝送されてくる多重化電話信号の下側周波
数帯に挿入されている、監視制御信号等のサービス信号
を受信するパイロット検出部の電源が他の回路と共通化
されているＦＭ受信装置において、前記パイロット検出
部と前記電源の間に、前記電源から前記パイロット検出
部への直流電力は通過させ、かつ少なくとも前記サービ
ス信号の一部の周波数帯の信号を阻止するフィルタを挿
入して構成しである。In order to achieve the above object, the FM receiver according to the present invention provides a power source for a pilot detection unit that receives service signals such as supervisory control signals inserted into the lower frequency band of a multiplexed telephone signal transmitted by FM. In an FM receiving device in which a circuit is shared with other circuits, DC power from the power supply to the pilot detection unit is passed between the pilot detection unit and the power supply, and at least part of the service signal is transmitted between the pilot detection unit and the power supply. It is constructed by inserting a filter that blocks signals in the frequency band.
前記構成によれば仮にパイロット検出部でトランジスタ
等のオン・オフ繰シ返しが発生しても、電源にはその周
波数は重畳されないので受信されるサービス信号は雑音
の少ないものとなり、本発明の目的は完全に達成される
。According to the above configuration, even if a transistor or the like repeatedly turns on and off in the pilot detection section, the frequency is not superimposed on the power supply, so the received service signal has less noise, which is an object of the present invention. is fully achieved.
以下、図面を参照して本発明をさらに詳しく説明する。Hereinafter, the present invention will be explained in more detail with reference to the drawings.
第４図は本発明の一実施例を説明するための図で、ＦＭ
受信装置の一部詳細図である。ベースバンド増幅器７お
よびパイロット検出器８は、電源線１３を介して共通の
直流電源に接続されているが、パイロット検出器８側の
電源線には、直流は通すがサービス信号の周波数帯は阻
止する低域通過フィルタ１７が挿入されている。そのた
めパイロット検出器８で繰シ返し周波数が発生してもフ
ィルタ１７によって阻止さ・れ、電源線１３を介してベ
ースバンド増幅器７を始めとする他の回路に漏洩するこ
とが無く、しだがつてサービス信号に対して雑音を与え
ることも無い。FIG. 4 is a diagram for explaining one embodiment of the present invention.
FIG. 3 is a partially detailed diagram of the receiving device. The baseband amplifier 7 and the pilot detector 8 are connected to a common DC power source via a power line 13, but the power line on the pilot detector 8 side passes DC but blocks the service signal frequency band. A low-pass filter 17 is inserted. Therefore, even if a repetitive frequency occurs in the pilot detector 8, it is blocked by the filter 17 and does not leak to other circuits including the baseband amplifier 7 via the power line 13. No noise is added to the service signal.
本図に挙げた実施例に低域通過フィルタを用いた場合を
例にとって示したが、直流を通過させて、サービス信号
の周波数帯を阻止するフィルタである限り、他の帯域阻
止フィルタ等のフィルタでも同様の効果が得られること
は言う１でもない。Although the embodiment shown in this figure uses a low-pass filter as an example, other filters such as band-rejection filters can be used as long as the filter passes direct current and blocks the frequency band of the service signal. However, it cannot be said that the same effect can be obtained.
なた、一般にはパイロット検出器８で生じる繰υ返し周
波数は、必らずしもサービス信号の全周波数帯におよぶ
とは限らず、その一部の周波数のみが発生する場合もあ
る。その周波数が予め知られている場合には、フィルタ
の阻止する周波数帯をその一部に限っても、全く同様の
効果が得られることは明白である。In general, the repetition frequency generated by the pilot detector 8 does not necessarily cover the entire frequency band of the service signal, and may occur only in a part of the frequency band. If the frequency is known in advance, it is clear that the same effect can be obtained even if the frequency band blocked by the filter is limited to a part of the frequency band.
以上、詳しく説明したように本発明によるＦＭ受信装置
は、受信される搬送周波数信号のレベルがスケルチレベ
ル以下になっても、サービス信号に悪影響を及ぼすこと
が無いという優れた特性を有する。As described above in detail, the FM receiving apparatus according to the present invention has an excellent characteristic that even if the level of the received carrier frequency signal falls below the squelch level, it does not adversely affect the service signal.
第１図は従来のＦＭ受信装置の一実施例を示す図、第２
図に第１図の一部詳細図、第３図はＦＭ受信装置だおけ
る使用周波数帯を説明するための波形図、第４図は本発
明によるＦＭ受信装置の一実施例を説明するための一部
詳細図である。
ｌ・・・端子 ２・・・ミキサ ３・・・局部発振
器４・・・中間周波数フィルタ
５・・・ＩＪ ミッタ増幅器 ６・・・ＦＭ復調器７
・・・ベースバンド増幅器
８・・・パイロット検出器 ９・・・端子１０・・・
阻止フィルタ １１・・・スイッチ１２・・・端子
１３・・・電源線
１４・・・多重電話信号 １５・・・パイロット信号１
６・・・サービス信号 １７・・・低域通過フィル・り
特許出願人 日本電気株式会社
代理人 弁理士 井ノロ 壽
第１図
才２図
第３図
才４図FIG. 1 is a diagram showing an embodiment of a conventional FM receiver, and FIG.
1 is a partially detailed diagram of FIG. 1, FIG. 3 is a waveform diagram for explaining the frequency bands used in the FM receiver, and FIG. 4 is a diagram for explaining an embodiment of the FM receiver according to the present invention. This is a partially detailed diagram. l...Terminal 2...Mixer 3...Local oscillator 4...Intermediate frequency filter 5...IJ Mitter amplifier 6...FM demodulator 7
...Baseband amplifier 8...Pilot detector 9...Terminal 10...
Blocking filter 11...Switch 12...Terminal
13...Power line 14...Multiple telephone signal 15...Pilot signal 1
6...Service signal 17...Low pass filter patent applicant NEC Corporation agent Patent attorney Hisashi Inoro Figure 1 Figure 2 Figure 3 Figure 4
Claims (1)
周波数帯に挿入されている、監視制御信号等のサービス
信号を受信するパイロット検出部の電源が他の回路と共
通化されているＦＭ受信装置において、前記パイロット
検出部と前記電源の間に、前記電源から前記パイロット
検出部への直流電力は通過させ、かつ少なくとも前記サ
ービス信号の一部の周波数帯の信号を口止するフィルタ
を挿入して構成したことを特徴とするＦＭ受信装置。An FM receiving device in which the power supply of the pilot detection unit that receives service signals such as supervisory control signals, which is inserted into the lower frequency band of the multiplexed telephone signal transmitted by the FM method, is shared with other circuits. A filter is inserted between the pilot detection unit and the power source to allow DC power from the power supply to the pilot detection unit to pass through, and to block signals in at least a part of the frequency band of the service signal. An FM receiving device characterized by comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23104582A JPS59122238A (en) | 1982-12-28 | 1982-12-28 | Fm receiver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23104582A JPS59122238A (en) | 1982-12-28 | 1982-12-28 | Fm receiver |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59122238A true JPS59122238A (en) | 1984-07-14 |
| JPS6354258B2 JPS6354258B2 (en) | 1988-10-27 |
Family
ID=16917411
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23104582A Granted JPS59122238A (en) | 1982-12-28 | 1982-12-28 | Fm receiver |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59122238A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008035413A (en) * | 2006-07-31 | 2008-02-14 | Fujitsu Ltd | Receiver and receiving method |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5033702A (en) * | 1973-07-25 | 1975-04-01 | ||
| JPS5115390A (en) * | 1974-07-30 | 1976-02-06 | Nippon Electric Co | |
| JPS53103611U (en) * | 1977-01-26 | 1978-08-21 |
-
1982
- 1982-12-28 JP JP23104582A patent/JPS59122238A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5033702A (en) * | 1973-07-25 | 1975-04-01 | ||
| JPS5115390A (en) * | 1974-07-30 | 1976-02-06 | Nippon Electric Co | |
| JPS53103611U (en) * | 1977-01-26 | 1978-08-21 |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008035413A (en) * | 2006-07-31 | 2008-02-14 | Fujitsu Ltd | Receiver and receiving method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6354258B2 (en) | 1988-10-27 |
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