JPH0234539B2 - DEIJITARUSHORIGATACHOTSUKOHENCHOSOCHI - Google Patents
DEIJITARUSHORIGATACHOTSUKOHENCHOSOCHIInfo
- Publication number
- JPH0234539B2 JPH0234539B2 JP3875084A JP3875084A JPH0234539B2 JP H0234539 B2 JPH0234539 B2 JP H0234539B2 JP 3875084 A JP3875084 A JP 3875084A JP 3875084 A JP3875084 A JP 3875084A JP H0234539 B2 JPH0234539 B2 JP H0234539B2
- Authority
- JP
- Japan
- Prior art keywords
- digital
- output
- quadrature modulation
- outputs
- modulation device
- 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 - Lifetime
Links
- 238000010586 diagram Methods 0.000 description 6
- 238000001228 spectrum Methods 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
- H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
- H04L27/36—Modulator circuits; Transmitter circuits
- H04L27/365—Modulation using digital generation of the modulated carrier (not including modulation of a digitally generated carrier)
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
Description
【発明の詳細な説明】
(技術分野)
本発明は、デイジタル処理形直交変調装置の改
良に関するものである。DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an improvement in a digitally processed quadrature modulation device.
(従来技術)
従来、相異なる2種類の基底帯域信号を各々デ
イジタルローパスフイルタで帯域制限した後、互
いに直交する搬送波で振幅変調して両者を加算処
理するデイジタル処理形直交変調装置は第1図に
示す如き構成であつた。(Prior Art) Conventionally, a digital processing type quadrature modulation device that limits the band of two different types of baseband signals using digital low-pass filters, amplitude modulates them using mutually orthogonal carrier waves, and adds them is shown in Fig. 1. The structure was as shown.
第1図は従来よりよく知られたこの種の装置の
一構成例を示すブロツク図であつて、デイジタル
ローパスフイルタ1−1,1−2、乗算回路2−
1,2−2、加算回路3、および直交する2つの
出力、換言すると互いに直交する搬送波を発生し
乗算回路2−1,2−2に出力する正弦波発振器
4から構成されている。 FIG. 1 is a block diagram showing an example of the configuration of this type of device, which has been well known in the past, and includes digital low-pass filters 1-1, 1-2, a multiplier circuit 2-
1, 2-2, an adder circuit 3, and a sine wave oscillator 4 that generates two orthogonal outputs, in other words mutually orthogonal carrier waves, and outputs them to the multiplier circuits 2-1, 2-2.
しかしながら、第1図に示す如き従来の構成で
は、乗算回路、加算回路、および正弦波発振器の
回路量が多くなり、したがつて価格面では高価と
なり、又、実装面では大きくなる等、の問題があ
つたのである。 However, in the conventional configuration as shown in Fig. 1, the number of circuits including the multiplier circuit, the adder circuit, and the sine wave oscillator is large, resulting in an expensive price and a large mounting area. It was hot.
(発明の目的)
本発明は、このような点を考慮してなされたも
ので、従来あつた乗算回路、加算回路、正弦波発
振器等を用いずに構成し、安価で、しかも小型化
を図つたデイジタル処理形直交変調装置を提供す
ることを目的とする。(Object of the Invention) The present invention has been made in consideration of the above points, and is configured without using conventional multiplier circuits, adder circuits, sine wave oscillators, etc., and is inexpensive and miniaturized. An object of the present invention is to provide a digitally processed quadrature modulation device.
(発明の構成)
すなわち、本発明はこの種の装置において、基
底帯域信号に接続され、異つたサンプル位相で動
作する第1と第2のフイルタと、前記両フイルタ
の出力を時分割的に走査し切替る回路と、デイジ
タル・アナログ変換器と、バンドパスフイルタを
順次接続したもので、この構成によつて上記目的
を達成するものである。以下、図面を用いて本発
明を説明する。(Structure of the Invention) In other words, the present invention provides a device of this type that includes first and second filters that are connected to a baseband signal and operate at different sample phases, and that scans the outputs of both filters in a time-divisional manner. A digital-to-analog converter, a digital-to-analog converter, and a bandpass filter are connected in sequence, and this configuration achieves the above object. The present invention will be explained below using the drawings.
(発明の実施例)
第2図は本発明に係るデイジタル処理形直交変
調装置の一実施例を示すブロツク図であつて、図
中、デイジタルローパスフイルタ5−1,5−2
は各々、入力信号a,bを受け、位相の異るサン
プルパルスc,dの駆動によりサンプリングし、
出力e,fを送り出す。時分割的に切替走査する
切替回路6では、前記出力e,fを受けると、そ
の切替走査により出力gを作成し、送出する。こ
の出力gは、デイジタルアナログ変換器7に送ら
れ、そのデイジタル信号はアナログ信号に変換さ
れて出力hを送出し、次いで、アナログのバンド
パスフイルタ8によつて直交変調され、出力iの
信号を送出する。(Embodiment of the Invention) FIG. 2 is a block diagram showing an embodiment of the digital processing type quadrature modulation device according to the present invention.
receive input signals a and b, respectively, and sample by driving sample pulses c and d of different phases,
Send out outputs e and f. When the switching circuit 6 which performs switching scanning in a time-division manner receives the outputs e and f, it creates an output g by the switching scanning and sends it out. This output g is sent to a digital-to-analog converter 7, which converts the digital signal into an analog signal and sends out an output h, which is then orthogonally modulated by an analog bandpass filter 8 to produce an output i signal. Send.
第3図は以上述べたデイジタル処理形直交変調
装置の動作を説明するタイムチヤートであつて、
図中のSは説明の為の時間基準である。又、デイ
ジタルローパスフイルタを駆動するサンプルパル
スc,dの周期Tは、搬送波周波数cの逆数に選
ばれT=1/cに設定される。このサンプルパル
スc,dは、ここではT/4の位相差を持つてお
り、したがつて切替回路6にあつては、時間基準
イの時に出力eを、時間基準ロの時に出力fを、
時間基準ハ,ニの時には無信号レベルの出力を
各々出力する出力g、換言すると出力hが得られ
るように構成されている。 FIG. 3 is a time chart illustrating the operation of the digitally processed orthogonal modulator described above.
S in the figure is a time reference for explanation. Furthermore, the period T of the sample pulses c and d for driving the digital low-pass filter is selected to be the reciprocal of the carrier wave frequency c, and is set to T=1/c. These sample pulses c and d have a phase difference of T/4 here, and therefore, in the switching circuit 6, the output e is output when the time reference is A, and the output f is output when the time reference is B.
The configuration is such that an output g, in other words, an output h, which outputs a no-signal level output is obtained when the time reference is C or D.
第4図は周波数スペクトラムによつて上記構成
のデイジタル処理形直交変調装置の動作の説明図
である。図中e,fは各々デイジタルローパスフ
イルタ出力の周波数スペクトラムを示し、e′,
f′は搬送波の位相を示すベクトルである。又、
i′はアナログバンドパスフイルタの伝送特性を示
し、iはアナログバンドパスフイルタによる直交
変調信号のスペクトラムを示している。 FIG. 4 is an explanatory diagram of the operation of the digital processing type orthogonal modulation device having the above configuration using a frequency spectrum. In the figure, e and f indicate the frequency spectrum of the digital low-pass filter output, and e′,
f' is a vector indicating the phase of the carrier wave. or,
i' indicates the transmission characteristic of the analog bandpass filter, and i indicates the spectrum of the orthogonal modulated signal by the analog bandpass filter.
ここで、以上第4図で示すように、本発明は直
交する2つの搬送波を得る為に異つた位相を持つ
たサンプルパルスを用いていることが明らかで、
以下、説明する。e,fの信号は各々、以下の(1)
式、(2)式で示すことが出来る。 Here, as shown in FIG. 4, it is clear that the present invention uses sample pulses with different phases to obtain two orthogonal carrier waves.
This will be explained below. The signals e and f are each expressed as follows (1)
It can be shown by equation (2).
e=(ap)・{∞
〓n=-∞
δ(t・nT)}
=(ap)・{1+cosωct+cos2ωct+……}
……(1)
f=(bp)・{∞
〓n=-∞
δ(t+T/4−nt)}
=(bp)・{1+cos(ωct+2π/4)
+cos(2ωct+4π/4+……} ……(2)
但し、T=2π/ωc
以上、(1)式、(2)式において、{ }内の第2項
に着目すれば明らかなように2つの搬送波は直交
したものとなつている。このことを図で示したの
が第4図である。e=(ap)・{ ∞ 〓 n=-∞ δ(t・nT)} =(ap)・{1+cosωct+cos2ωct+……}
……(1) f=(bp)・{ ∞ 〓 n=-∞ δ(t+T/4−nt)} =(bp)・{1+cos(ωct+2π/4) +cos(2ωct+4π/4+……} ……( 2) However, above T = 2π/ωc, in equations (1) and (2), if you pay attention to the second term in { }, it is clear that the two carrier waves are orthogonal. This is illustrated in Figure 4.
なお、上式中、はたたみ込み積分を示し、p
はデイジタルローパスフイルタのインパルスレス
ポンスである。 In addition, in the above formula, the convolution integral is shown, and p
is the impulse response of the digital low-pass filter.
(発明の効果)
以上詳述のように本発明によれば、この種の装
置において、異るサンプル位相を2種用意してデ
イジタルローパスフイルタを駆動し、その出力を
切替えて得るように構成したので、従来の如き乗
算回路、加算回路、正弦波発振器は不用となり、
したがつて、安価なそして小型化が可能な、しか
も必要とされる特性を損うことのないデイジタル
処理形直交変調装置を提供出来る優れた効果が期
待出来るのである。(Effects of the Invention) As detailed above, according to the present invention, in this type of device, two types of different sample phases are prepared, a digital low-pass filter is driven, and the output is obtained by switching. Therefore, conventional multiplier circuits, adder circuits, and sine wave oscillators are no longer required.
Therefore, it is possible to expect an excellent effect of providing a digitally processed quadrature modulation device which is inexpensive and can be miniaturized, and which does not impair the required characteristics.
第1図は従来のデイジタル処理形直交変調装置
の一構成例を示すブロツク図、第2図は本発明に
係るデイジタル処理形直交変調装置の一実施例を
示すブロツク図、第3図は第2図で示す装置の動
作を説明するタイムチヤート、第4図はスペクト
ラムによる説明図である。
1−1,1−2,5−1,5−2はデイジタル
ローパスフイルタ、2−1,2−2は乗算回路、
3は加算回路、4は正弦波発振器、6は切替回
路、7はデイジタルアナログ変換器、8はバンド
パスフイルタである。
FIG. 1 is a block diagram showing a configuration example of a conventional digital processing type quadrature modulation device, FIG. 2 is a block diagram showing an example of a digital processing type quadrature modulation device according to the present invention, and FIG. FIG. 4 is a time chart explaining the operation of the device shown in the figure, and FIG. 4 is an explanatory diagram using a spectrum. 1-1, 1-2, 5-1, 5-2 are digital low-pass filters, 2-1, 2-2 are multiplication circuits,
3 is an adder circuit, 4 is a sine wave oscillator, 6 is a switching circuit, 7 is a digital-to-analog converter, and 8 is a bandpass filter.
Claims (1)
変調し、加算するデイジタル処理形直交変調装置
において、 基底帯域信号に接続され、異つたサンプル位相
で動作する第1と第2のデイジタルローパスフイ
ルタと、 前記両フイルタの出力を時分割的に走査し、切
替える回路と、 デイジタル・アナログ変換器と、 バンドパスフイルタとを順次接続して構成した
ことを特徴とするデイジタル処理形直交変調装
置。[Claims] 1. In a digital processing quadrature modulation device that amplitude-modulates a baseband signal using carrier waves orthogonal to each other and adds the amplitude, first and second signals are connected to the baseband signal and operate at different sample phases. Digital processing quadrature modulation characterized in that it is configured by sequentially connecting a digital low-pass filter, a circuit that time-divisionally scans and switches the outputs of both filters, a digital-to-analog converter, and a bandpass filter. Device.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3875084A JPH0234539B2 (en) | 1984-03-02 | 1984-03-02 | DEIJITARUSHORIGATACHOTSUKOHENCHOSOCHI |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3875084A JPH0234539B2 (en) | 1984-03-02 | 1984-03-02 | DEIJITARUSHORIGATACHOTSUKOHENCHOSOCHI |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS60183855A JPS60183855A (en) | 1985-09-19 |
JPH0234539B2 true JPH0234539B2 (en) | 1990-08-03 |
Family
ID=12533974
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3875084A Expired - Lifetime JPH0234539B2 (en) | 1984-03-02 | 1984-03-02 | DEIJITARUSHORIGATACHOTSUKOHENCHOSOCHI |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0234539B2 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0693844B1 (en) * | 1994-07-20 | 2005-12-07 | Nippon Telegraph And Telephone Corporation | Digital quadrature modulator |
EP0760567A3 (en) * | 1995-08-30 | 2000-09-06 | Siemens Aktiengesellschaft | Digital QAM modulator |
-
1984
- 1984-03-02 JP JP3875084A patent/JPH0234539B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
JPS60183855A (en) | 1985-09-19 |
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