JPS58120353A - Msk modulating system - Google Patents

Abstract

PURPOSE:To realize the system inexpensively with a simple circuit, by obtaining a phase continuous frequency shift keying wave having a frequency twice the desired frequency and frequency-dividing the wave into two to obtain the desired MSK wave. CONSTITUTION:An output (a) of a 7.2kHz oscillator 9 is frequency-divided at a 1/2 frequency divider 10 and a 1/3 frequency divider 11 and becomes 3.6kHz and 2.4kHz pulse signals at signals (c) and (d) and inputted to a switching circuit 12. The outputs of the dividers 10, 11 are ANDed at an AND circuit 16 to obtain a clock (e), 1.2kHz in frequency, which is applied to an FF17. An input base band signal is synchronized with the clock (e) and inputted to a switching circuit 12. The circuit 12 gives an output of 3.6kHz or 2.4kHz pulse signals depending on that the input base band signal is mark or space. An output signal (g) of the circuit 12 is inputted to an FF13, which gives a signal (h) with a delay, and this signal (h) is divided at a 1/2 frequency divider 14 to obtain the specified MSK wave.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical field of @Ming The present invention converts digital signals into phase-continuous mtII! The modulation method using M8Ktll, which has a modulation index of 0.5 among the number shift Imaichi ink (hereinafter abbreviated as F8), is used.
(b) A block diagram of an HTR8 conversion type using a voltage controlled oscillator of the conventional FA, which is a convergence between the conventional technology and the conventional technology. This is the block of the MBKKm system of the conventional 2-period system.L in 1 is the voltage controlled oscillator, 2 is the mHz oscillator, and 3 is the mark signal count of l1rHxThgaikiyosim11g. A frequency divider with a frequency division ratio of m/# to obtain, 4 is also n H
A frequency divider with a frequency division ratio of n/I to obtain the space number frequency division number of z, 5 is a clock generator, 6 is a switching control circuit, 7 is a switching circuit, and 8 is a 17-inch circuit. In the case of wLl-, MSK modulation is performed by changing the oscillation frequency of the voltage side control oscillator 10 depending on the mark/space of the human base punt signal so that the l index becomes 0.5, but in this case, voltage control 41 bag vibrator has the disadvantage that it is a weak point.The n/J frequency divider 4 inputs pulse signals of m Hz and II Hz frequencies with different phases of 180 jt to the switching circuit 7 (however, IJm -nj
The output of the 7-rip 70 knob 8 is synchronized with the base punt qi via the lip 70 knob 8), and the switching control circuit 6 corresponds to the mark/space of the input base punt signal. For example, when marking is performed, the p switching circuit 7 is controlled by the control @ symbol.
It outputs a pulse signal of fi ltg and when it is a space, it outputs a pulse fi of fi ltg! However, in this case, those who perform phase-continuous +=F8K with a variable index of 0.5 are using MSK modulation to output the input base punt signal, for example, the mHz pulse signal at the time of marking. Is the phase of the pulse signal of l1l(z at the next space OK also of the output of Q of the nZlI frequency divider 4?
Since it is necessary to select whether to output 01 with a different phase, the # (b) path 6 on the switching side requires a circuit to make this determination, which has the disadvantage that the circuit becomes a drawing line and becomes a price. (C) Object of the invention The object of the invention is to eliminate the above-mentioned drawbacks.

MSKt with predetermined mark and space frequencies
A phase continuous FSKI with twice the desired 18 wavenumbers at mark/space of the input base punt signal to obtain &
& is obtained by the leading two-frequency switching method, and then the mosquito F
To provide a MISK modulation method which can be put to practical use at low cost with a simple circuit that does not require a complicated switching control circuit by dividing the frequency of an SK wave by two.

(d) Structure of the Invention The present invention 111 has the above-mentioned purpose. tl of the pulse at the mark that falls within the length of 1 bit!
If the number is tatami mat, the pulse wave number at space time will also be automatically! 1, and the phase relationship between the Zug time pulse signal and the space time pulse signal at the conversion point of the first input base punt signal is continuous, and the point Kfl is where it is possible to always make it continuous.

The frequency of the pulse signal at the time of mar and space is twice the frequency of the desired M8 wave, and the bit rate of the input base punt signal is determined by N-frequency. The input base punt signal is synchronized with the matching pulse, and f, L? It is characterized by simply switching the above pulse signal to obtain a phase continuous FSK branch with a modulation index of 1 at twice the desired frequency, and dividing this by a single VC2 to obtain M8 from k (el @ The following is an explanation of the implementation of the present invention according to the figures attached to f11K.In summary! 1JFi The M8 of the embodiment of the present invention is a block diagram of the modulation method, and Figure 4 shows the various parts in the case of 3-. In the waveform time chart, the waveform shown on the left side is #i3, the symbol attached to #3.〇 In the figure, #9 is a 17.2KHz oscillator, and 10.14 is a frequency divider with a frequency division ratio of 172. , 11 is a divider with a frequency division ratio of 173, 12
Fi switching circuit, 13.17 Fi flip-flop (hereinafter abbreviated as FF), 15 knot (lo) circuit, 16 is an AND circuit ◎ In the example of Fig. 3, the frequency of the input bass punt signal when it mars is 1. Frequency a in space at 8KHz is 1.2KHz, Pitley) Fil, M'BK at 2Kbit/sec
This shows the case where you get a branch. 1.8KM! and 1.2KHz 2+WI m5
113.6KHz and 2.4KHz bit rate 1
．． In order to obtain a clock of 2Kbtt/5ecK4 maa, the frequency of the oscillator 9 is set to F17.2 KHz, and the output of the oscillator 90aK shown is divided by 172.
The frequency is divided by #10 and 1'/3 frequency divider 11, respectively.
, dK indicating 3.6 KHz and 2.4 K Hz are input to the 9 switching 1111M12, and the outputs from the 1/2 frequency divider 10 and 113 divider 11 are logically processed by the AND circuit 16. 1.2KH of frequency equal to the bit rate of the input bass punt signal such that the product is 9eK! The clock is obtained and supplied to the clock terminal of the FF 17, and inputted to the switching circuit 12 in synchronization with this click as shown in the input bass punt signal C% fK. In this case, the pulse signals of 3.6KHz and 2.4KHz and the pulse signals of 1.2KHz are the same. Obtained from a 7.2KHz oscillator 9 with a frequency of -9
, full1m again! Since the number 11 is 1, 3 at the mark
．． 1F13 integers of 6KHz, 2.4KHz wave at 1H9 or space is 2 integers, synchronized so that each pulse rises at the rising point of the clock, 3.6KH
0FF13 is marked/ This is to prevent malfunction of the 172 frequency divider 14 in the latter stage due to whisker-like noise generated by the space switching WIK, and is not necessary depending on the winding.◎Switching circuit 1
The output from 2 also shows jlK! When a signal is input to the FF 13 and a pulse signal as shown by bK, which is the inverted pulse signal from the 2KHz oscillator 9 in the not (ro) path 15, is added to the FF 13's 61 terminal, the output of the FF 13 is as shown in FihK. When this signal is divided by the 1/2 divider 14, the mark #1.8KHz as shown by iK becomes 1 at the space time.
．． 2KHz MSK wave cannot be obtained.0 In the time chart in Figure 4, it is assumed that the clock operates at the rising point of the clock indicated by #ie minute period and FFFise bK, but it may be summed to operate at the falling 9 points.0 (f) Effects of the Invention As explained in detail above, according to the present invention, the quality circuit in the M8 can be constructed with a very simple digital circuit consisting only of logic elements, resulting in lower costs. simultaneous! /c It has the effect of making it easier to horizontalize collection.

[Brief explanation of the drawings] Fig. 1 is a block diagram of the modulation method for M8 using the conventional voltage-controlled W knee shaker and the modulation method for 9 M8. , I! 4- is a time chart of the waveforms of each part in Figure 3. 5#'i haze ivy generator, 7.12 is a switching circuit, 8°13.17 is FF, 9 is a 7.2KHxQ vibrator, 10°14 is a frequency divider with a frequency division ratio of 1/2, 11 is a frequency divider with a division ratio of 173, 15 is a NOT circuit, and 16 is an AND circuit.

Claims (1)

[Claims] Circumference t11 when marked with phase continuous frequency shift key ink
111 is ffl)l z, msa when space is n
In a modulation method with a Hz a-variance index of 0.5, Oka-
Divide the frequency of the station wave number tfI# by 2 m from K
Obtain the frequency @ of Hs e 2 ” Hz, and these @
The number was switched to correspond to the mark and space shape of the human base panto number M, which was synchronized to the clock pulse, which was strange to the bit rate of the baseband signal obtained. A MS K characterized by obtaining a phase continuous frequency shift keying wave having a frequency of 2 mHz during marking and a frequency of 21111g during space, and then dividing the frequency of the frequency shift key ink wave by two.
(gi nimum, shift, key
tflg) Modulation method◎