JPS58145259A - Multivalued signal generator - Google Patents

Abstract

PURPOSE:To generate easily a wave-shaped multivalued signal with good accuracy, by locating various different resistors for an output of a binary transversal filter and selecting one of them according to a level control signal. CONSTITUTION:The selection of the level of quadrivalue signal is determined with a level control signal inputted to a terminal 10. A single pulse is inputted to binary transversal filters BTF30, 31 from a resistor selector 20 in synchronizing with a clock inputted to a terminal 11. The BTEs 30, 31 make response with opposite polarity. Thus, the waveform of inverted polarity is inputted to a resistor group 40. The rsistor group 40 is provided with resistors of resistance values R and 2R, and the selection of the resistors depends on a signal outputted from a resistor selector 20 via a delay line. The output signal level of the resistor group 40 depends which of the resistance values R, 2R is to be connected, and the relation between the resistance value and the output signal level are in the inverse proportion.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical generator for use in digital .mu. communications, which generates waveform-shaped multi-end signals.

One conventional signal generator of this type was the one shown in FIG. Figure 1C? and ) is the 2+di1m input terminal,
(2) is a clock input terminal, 13) is a clock input terminal (2nd ζ is the number of dm of the input clock, M4f!t (M
: @Number) and output it multiplied by 3, (4) is 2(d+
, the signal input to the i input terminal (1) is multiplied by the multiplier (3)
A shift register that shifts one step at a time using a clock from
(5) is this shift register, one of the outputs of each stage of 4) is a group of resistors connected in 11 columns to the Pi# stage signal D), +61 is the output from this resistor group t512)) The adder that converts the stepped No. 15 into IJuJr-, (7) is the output D) of this hOx unit (6) by removing the high
! ! A harmonic filter eliminating low-pass filter (L P
F ) and +MI are signal output terminals.

Next, the operation sequence will be explained. The 21 direct (binary) signal input to the input terminal is sent to the clock multiplier (31
Due to the output clock, the data rate of M after API
The data is shifted one stage at a time in the shift register +41.

However, in the figure, line 15, which shifts in the shift register 4), is omitted. The output of the shift register (4) becomes an input signal to the next stage register, and at the same time
The two outputs become input signals to the resistor group 15+. The resistor group 15) consists of a number of resistors equal to the number of stages of the shift register (4), and the number of resistors in each stage is +4.
The output of Q1 is connected to one of Q. The step-like signal output from the shift register (4) is transmitted to the resistor group 16.
A stepped signal having an amplitude inversely proportional to the resistance value (this is called a tap coefficient) is input to the adder 16. shift register +4) by adder (6)
After No. 1a equal to the number of stages is added, harmonic removal L
'i' F 171 produces a smooth continuous signal, which is output from the output terminal (8).The relationship between the time waveform and frequency spectrum at this time is shown in Figure 2. However, the M(Z) value may be any value as long as it is 2 or more, and 1a) is the signal waveform to be finally generated, and the 4-wavenumber spectrum is limited to a band ~. 1b) is the clock multiplier (31
Time domain waveform and frequency spectrum when the signal output from Q or Q is an impulse when the shift register (4) is driven with the output clock (T/2 period, T: length of 1 symbol signal) be. (C) shows the resistor group (
Figure 2(d) shows the case where each resistance value in 5) is selected to correspond to the amplitude value of the desired signal waveform.
These are the time domain waveform and frequency spectrum when the output of step 4) is a four-way stepwise waveform. If the output staircase waveform of the adder (6) is as shown in the d1 diagram, then the l16a wave removal L
Harmonics removed by P F i71 (5n, 1m)
The desired waveform shown in the figure is obtained.

The signal generator shown in FIG. 1 is called a binary-transpersal filter (MTF).

The conventional LJI generator that generates waveform-shaped signals had the above IC configuration, so with this configuration, it could only always generate waveforms of the same level and had the disadvantage of not being able to generate multilevel signals. .

This invention was made in order to eliminate the long-standing problems of the conventional filter as described above, and by placing each resistor with a value of II at the output of the conventional binary transversal filter, The object is to provide a multiple +1 signal generator capable of generating multiple III signals by selecting one of its resistors.

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings. Third
The figure is a block diagram of the 4-value 1g signal generation. 1 and 2 are the level control signal input terminals for specifying one of the 4-value signals, (■1 is the clock input terminal, and ω is the Using a level control signal specifying one of the four-valued signals and a clock as input signals, two binary signals are sent to the binary transversal filter m, @0-ζ, and at the same time, the resistance values of each Resistance selector m, t that sends information on which resistor to select to the built-in resistor group
sD is a binary transparser/L/ that performs waveform shaping.
filter (BTF), and if its tap coefficients are (an%, I an'), @ B 'wm-a
n (na=i a..."a LaL: number of V resistor stages) - is a resistor group consisting of various resistors and switches with value S, complement is B T F wire, @υ is the signal in 2 Delay a is used to correct the delay time of resistor group - so that the switching of the two resistors in resistor group - is performed correctly. This is a multi-level signal output terminal.

The operation of this device will be explained below. Assuming that the output level of the four-level signal is 3A, ^, -^, -3A (A: constant), the selection of the level is determined by the level control signal inputted to the terminal u1ζ. In synchronization with the clock input to the terminal (Front 1), a single pulse with a length of pulse gT (T: IF port length) is output from the resistor selector as an output signal *1. BTFJl and Cll1C for the waveform are input through b. I
ITF (D rip coefficient is m for BPF@l and @O.
a'm-In (D-related, for example BTF
cIl's single/(ρ) If the response is an upward response, then BT
The single/cursive response of FlIII is completely isomorphic, with a downward response of opposite polarity.

In this way, the opposite waveform is input to the resistor m-.The resistor group- has two resistors with resistance values k and 2λ, and the selection of the resistor is output from the resistor selection IiI■. The output signal level of the resistor group according to the signal passed through the delay 41- is determined by which of the two resistors it and 2i is connected.The resistance value and the output signal level are inversely proportional. There it is.

That is, when the output signal level V is 2, a resistor with a resistance of 1 m and 21 L is connected to B. Also, if the output signal level is -A, a resistor 111 is connected to the output of BTF 迤υ.
A resistor of 2M is connected, and if the output 1J level is 12A, a resistor of 8TFlυ is connected to the output. The outputs of the resistor group are added together by the adder and output from the output terminal. The waveforms of the signals ko to f in each part of Fig. 443 for a single pulse are shown in Fig. 4 1m) to (fl,
In Fig. 4 1el, when the value of the resistor connected in the resistor group is 艮, the waveform is Ipaii2^, and when it is 21L, it is the waveform to amplitude, and in (f), the value of the resistor is 2, a waveform with an amplitude of -2 is obtained, and when λ, a waveform with an amplitude of -2 is obtained. As an example, in FIG. 5, the solid line shows the 4-value signal waveform, and the broken line shows the case where the waveform is not dominantly shaped by simultaneous 6ζBTF. It is clear that D) can be realized even in the case of Adjustment of this signal level is possible by a level V shift circuit.

Although the multi-11 signal generator itself has been described, this multi-+m < Can be used as Examples of multilevel modulation methods include a multiphase phase modulation method, a multilevel quadrature amplitude fil method, and the like.

Figure Wi6) and lbl show the signal space distribution diagrams of the 8-phase phase modulation method and the 16-value orthogonal amplitude conversion method. This is an example of the 8-phase phase shift system.
In the figure, (101) to (103) are data input terminals, (111) to (112) are resistance selectors, BTF,
The multi-value signal generator (121) is composed of a group of resistors;
(122) is the modulator, (131) is the local oscillator, (14
1) rotates the phase of one of the two outputs of this local oscillator (131) by ff/2, ff1l! [12
2) to make the phase of the carrier wave input to the modulator (121) orthogonal to the phase of the carrier wave input to the modulator (121).
51st revision @ 13 (121) A combiner 1112 that linearly synthesizes the modulated waveform modulated by r (122), (161) is the 8-phase phase modulated wave output terminal.Next, the operation of this modulation section will be explained.・Data input terminals (101) to (10
The three code strings input to 3) are sent to a multilevel signal generator (1
11) It is input to 3 (112) and serves as a control signal to the resistor selector and resistor group that determines the output signal level of the multi-E signal generator. Multilevel signal generator (111), (112
) The signal whose waveform has been shaped by the tap coefficients of the built-in BTF has four-level output levels ms, at, -
After becoming either at or -am, the change m 1
Input to one input port of Il (121) -r (122). On the other hand, the carrier wave output from the local oscillator (131) is split into two, and then a part is directly input to the f modulator (121).
), and a part of the signal is shifted in phase by π/2 by a phase shifter (141) and then input to an fM unit (122). In other words, the phases of the carrier waves input to the fdl units (121) and (122) are orthogonal ν, and these variations HA @ (121
) (122) by linearly combining the outputs of n (151), the output terminal (161) is
) A modulated waveform that is phase-modulated in one of the signal space layout diagrams will be obtained.For 2 or more, the multilevel signal generator is
Although one problem has been described when applied to the driver circuit of A, this can also be applied to other multi-phase phase modulation systems and multi-level single quadrature amplitude modulation systems.

As described above, according to the present invention, a multiple 1-1d signal generator is provided with a binary transversal filter and various values cascade-connected thereto, so that a desired number of signals can be obtained.
Select one of the above resistors depending on the N level, and so on 411! As a result, it is possible to generate a waveform-shaped multi-level signal in an easy-to-understand manner.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a conventional signal generator that generates a signal with an excellent waveform, Figure 2 is a diagram of the operation when generating a signal with the above-mentioned signal generator, and Figure 3 is a diagram of the present invention. -*! A block diagram showing the multilevel 4t1wj@generator according to the embodiment, FIG. 4 is a signal waveform diagram of each part of the ff3 diagram, and FIG.
- Diagram showing an example of the multi-end No. 15 output waveform of the signal generator, 1
Figure 1g6 (al, ibl is a diagram of the A5 space arrangement of the 8-phase phase modulation system ν and the 16-value quadrature amplitude modulation system for detailed explanation of this invention, and Figure 7 is an example of the application of this invention. It is a block diagram of the first part of the 8-phase phase modulation system. ...Delay line, Rishi [Koto...] nko calculator. Representative Makoto Yomano
-Figure 4 H-T-1 Figure 5Figure 6 (b) ch

Claims (1)

[Claims] Mountain 211! A transversal signal generator that shapes the waveform of an input signal and outputs it, and a resistor D) each having a value inversely proportional to the desired output amplitude. The resistor group that outputs multi-value 1N in summer and the level system (incorporated) signal cloud, so the above resistor a
Among the group D), a multi-sized valve generator is characterized in that it is equipped with a resistance multiplier for selecting a resistor of f# for the output of the above-mentioned 1-g optical generator.