JPS592419B2 - phase modulator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a phase modulation device with a simplified circuit configuration in a very high frequency region such as a millimeter wave band.

A carrier wave digital transmission system is already in practical use as one means of information transmission.

In addition, in recent years, the sub-millimeter wave band (18GH
2-21GH2), millimeter wave band (40GH2-80GH2
) has been developed. Among these methods, if we focus on the modulation method, we find that the direct modulation method, which applies direct phase modulation to the output carrier signal, is effective in terms of simplifying the circuit configuration, but on the other hand, it becomes unstable as the carrier frequency increases. This makes it difficult to realize a phase modulator with high performance. Therefore, there are no examples of direct modulation methods in the millimeter wave band that have entered the practical stage, and there are only examples using other methods. For example, as seen in millimeter wave band digital transmission systems,
This is a so-called heterodyne phase modulation method in which phase modulation is applied to an IF frequency of 1.7GH2 and the modulated wave is raised to a frequency in the millimeter wave band using a frequency converter. This method has the disadvantage that, compared to the direct modulation method, an extra IF local oscillator and frequency converter are required in the constituent unit, making the circuit configuration more complicated. An object of the present invention is to provide a phase modulation device that can be applied to millimeter wave band carrier frequencies with a simplified circuit configuration that eliminates the above drawbacks.

A detailed explanation will be given below with reference to the drawings.

Figure 1 shows a heterodyne type two-phase phase modulator, with 1
is an IF local oscillator, 2 is a 0-π phase modulator, 3 is a frequency converter, and 4 is a millimeter wave band local oscillator.

The operation will be briefly explained below. A 0-π phase modulator 2 applies 0-π phase modulation to the carrier signal from the IF local oscillator 1 corresponding to the input data signal, and the modulated wave signal is converted into a millimeter wave band signal by a frequency converter 3. It becomes a modulated wave signal.

Here, the frequency relationship in each part is IF: The frequency of local oscillator 1 is fIF) The frequency of millimeter wave band local oscillator 4 is fRF
Then, the output frequency fout of the frequency converter 3 is f0u
It is expressed as t=fRF±fIF. Therefore, by extracting either the upper sideband wave or the lower sideband wave, a phase modulated wave signal in the millimeter wave band can be obtained. This method requires an extra frequency converter 3 and an IF local oscillator 1 compared to the direct modulation method, and has the disadvantage that the circuit configuration is complicated. However, with the current technology, it seems difficult to realize a direct modulation method in the millimeter wave band. The present invention
The present invention provides a phase modulation device that has a simplified circuit configuration and can be applied to the millimeter wave band, except for the above drawbacks.

FIG. 2 is a block diagram of an embodiment of the multiplier type two-phase phase modulator according to the present invention, where 5 is a quasi-millimeter wave band local oscillator, 6 is an O-(π/2) phase modulator, and 7 is a doubler. It is.

The carrier signal of the quasi-millimeter wave band local oscillator 5 is O-(π/2)
The phase modulator 6 also applies π/2 phase modulation to the input data signal. This modulated signal is doubled by a doubler 7. Here, assuming that the output frequency of the quasi-millimeter wave band local oscillator 5 is f1 and 20 GHz, the output frequency of the doubler 7 will be 40 GHz expressed by F2-2f1.
Also, the amount of 0-(π/2) phase change is Sln2(2πFlt
+θ)=? At the output end of the doubler 7, the carrier frequency is doubled and doubled, such as 1H2(2πFlt+θ)/2. Therefore, from the above explanation, a carrier wave frequency of 40 GHz (7) O-π phase modulation wave signal can be obtained as the output of the doubler 7. Here, quasi-millimeter wave local oscillator 5 and O
-(π/2) phase modulator 6 is already in practical use,
The configuration shown in FIG. 2 can be fully realized using these. Also, the circuit configuration is simpler than that of the heterodyne phase modulator shown in FIG. In the above description, 2 was selected as the multiplication order of the multiplier, but this may be any number.

In this case, when the multiplication order is m, the carrier wave frequency Fl, f
2 and the phase change amount θ of the phase modulator, the following relationship must be satisfied. T=F2/Fl, θ3π/MOAlso, although the explanation in FIG. 2 was about a two-phase phase modulator,
The present invention can be applied to a 2n phase (n=1, 2, 3...) phase modulation device.

In other words, 2n phase (n
=1,2,3,...
), and the number of radians (1/2) t-1 radians (however, the value of t takes n values in sequence, such as N, n-1, n2,...). A configuration may be adopted in which n phase modulators each having a phase shift amount are connected in series in an arbitrary order, and m multipliers are connected to the output ends thereof.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional heterodyne type two-phase phase modulation device, and FIG. 2 is a block diagram of an embodiment of a multiplication type two-phase phase modulation device according to the present invention. In the figure, 1... IF band local oscillator, 2...
...0-π phase modulator, 3... Frequency converter, 4... Millimeter wave band local oscillator, 5...
・Quasi millimeter wave band local oscillator, 6...0-(π/2
) phase modulator, 7... double multiplier.

Claims (1)

[Claims] 1 2^n phase (however, n
= 2, 3, 4, ...), the carrier frequency f_2 (however, f_1=mf_2, m=2, 3
...), and π/m(1/2)^l^-^
1 radian (however, the value of l is n, n-1, n-
It takes n values like 2... ) A phase modulation device comprising a multiplier that connects n phase modulators in series and multiplies the output by m.