JPS61248603A - Sampling phase comparator circuit - Google Patents

Abstract

PURPOSE:To attain the operation up to a high frequency by connecting a stub in parallel with a transmission line tying a diode generating a pulse synchronously with a reference signal and a phase comparator element comparing the phase of the pulse with that of a signal to be sampled. CONSTITUTION:The reference signal is fed to a diode 2 to produce a pulse synchronously with the reference signal, the pulse signal and the signal to be sampled are fed to the phase comparison element 3 to obtain an output corresponding to a phase difference between the reference signal and the signal to be sampled. The 2nd transmission line 6 is connected between ground and the 1st transmission line 5 connecting the diode 2 and the phase comparison element 3 in the sampling phase comparison circuit. Thus, a pulse waveform generated in the step recovery diode 2 is sharpened more, the output voltage is increased and the circuit acts sufficiently like a phase comparator even in the frequency of the signal to be sampled of nearly 20-25GHz.

Description

[Detailed Description of the Invention] [Summary] In a sampling phase comparison circuit used in a phase-locked oscillator for an ultra-high frequency band, a diode that generates a pulse synchronized with a reference signal and a phase of this pulse and a sampled signal are compared. By connecting stubs in parallel to the transmission line connecting the phase comparison element, we were able to obtain a device that can be used at higher frequencies.

[Industrial application field]

The present invention relates to an improvement in a sampling phase comparator circuit used in a phase-locked oscillator for ultra-high frequency bands.

Generally, the components of a phase-locked oscillation circuit used in an ultra-high frequency band include an ultra-high frequency band oscillator two-phase comparator circuit, a low-pass filter, and a circuit that detects when phase synchronization is lost and resynchronizes it. However, unless the characteristics of each individual circuit are good and stable, it cannot function adequately as a phase-locked oscillator.

On the other hand, since the frequencies used are increasing year by year, a phase comparator circuit that operates up to as high a frequency as possible is required.

[Conventional technology]

FIG. 5 shows a circuit diagram of a conventional example of a sampling phase comparison circuit, and FIG. 6 shows a waveform diagram of FIG.

Note that the numbers on the left side of FIG. 6 indicate the waveforms with the same numbers in FIG.

Therefore, the operation shown in FIG. 5 will be explained with reference to FIG.

In FIG. 5, for example, the number 1 is applied to the terminal lN-1.
A reference signal of 0 to several 100 Mllz is applied to a diode (for example, a step recovery diode) 2 via a transformer 1, and positive and negative pulses synchronized with the reference signal are obtained (Figure 6 - ■ is a positive pulse). (only shown),
This pulse is applied to phase comparison elements (eg, Schottky barrier diodes) 3-1 and 3-2.

On the other hand, from terminal lN-2, several G
A high frequency signal of approximately Hz is detected by the phase comparison element 3-1.3.
-2, but due to the above-mentioned pulses, Fig. 6-■
As shown in Fig. 6, the output voltage corresponding to the phase difference between the reference signal and the sampled signal (the part indicated by the dashed dotted line in Fig. 6) is taken out from the terminal 011T (see the conventional example in Fig. 3). .

Here, if the phases of the two signals are synchronized, the same points of the sampled signal are sampled, so a constant output voltage can be obtained, but if they are asynchronous, the sampling points are shifted, so the output voltage changes. . Therefore, the phase of the sampled signal is controlled and synchronized with the reference signal so that this voltage becomes constant. is exactly the same as in FIG.

Here, +Vd and -vg indicate the power supply of PET.

Note that this sampling phase comparator circuit has a size of approximately 6 x 7 m, for example.
It is formed using chip parts and strip lines on an alumina substrate of M, but in order to prevent the above pulse waveform from changing or causing unnecessary resonance and reducing the output voltage, there are special connections between each circuit element and the transmission line. The length is kept as short as possible.

[Problem that the invention seeks to solve]

However, as shown in the conventional example in Fig. 3, this sampling phase comparison circuit has a frequency of about 10G.
When the voltage is higher than llz, the output voltage decreases and becomes 20 to 25.
There is a problem that it is not practical in the GIIz band.

[Means for solving problems]

The above problem can be solved by connecting the second transmission line 6 between the first transmission line 5 connecting the diode 2 and the phase comparison element 3 and the ground as shown in the principle block diagram of FIG. This problem is solved by the sampling phase comparison circuit of the present invention.

[Effect]

In the present invention, the second transmission line is connected between the first transmission line and ground.

As a result, the pulse waveform generated by the step recovery diode becomes sharper, the output voltage becomes larger, and the frequency of the sampled signal increases to approximately 20 to 25 GH.
Even z can now function satisfactorily as a phase comparator.

〔Example〕

FIG. 2 shows a circuit diagram of an embodiment of the present invention of a sampling phase comparison circuit.

In the figure, the structure of the second transmission lines 6-1 and 6-2 is, for example, a line with a width of 0.1 m and a length of about 1.5 to 2.5 mm, with one end connected to the first transmission line 5-2. 1.5-2, and the other end is grounded. At this time, the above-mentioned pulse width is narrower than in the conventional case, the waveform becomes steeper, and the output voltage obtained from the terminal OUT also increases.

It has been experimentally found that when the length is set to approximately 0, the peak value of the pulse becomes extremely small and the output voltage drops significantly.

Figure 3 shows the measured data in Figure 2, and the reference signal is 100
The relationship between the output voltage and the sampled frequency is shown when the input voltage is +17 dBm at MHz and the input power of the sampled signal is -7 dBm.

As shown in the figure, the output voltage is increased compared to the conventional one, and the curve is smooth, so there is no effect of resonance, and the device operates satisfactorily as a phase comparator up to about 20 to 25 GHz.

FIG. 4 shows a circuit diagram of another embodiment of the invention.

As shown in the figure, since FET 4 is used as a phase comparison element, transmission line 5-3 and second transmission line 6-3
becomes one. However, as in the case of Fig. 2, about 20~
25Gl (works well up to z).

〔Effect of the invention〕

As described in detail above, there is an effect that a sampling phase comparator circuit that can be used practically up to the frequency of the sampled signal of approximately 20 to 25 GH2 has been obtained.

[Brief explanation of drawings]

Fig. 1 is a principle block diagram of the present invention, Fig. 2 is a circuit diagram of an embodiment of the present invention, Fig. 3 is a comparison diagram of output voltages of the present invention and a conventional example, and Fig. 4 is another embodiment of the present invention. FIG. 5 is a circuit diagram of the conventional example, FIG. 6 is an operating waveform diagram of FIG. 1, and FIG. 7 is another circuit diagram of the conventional example. In the figure, 2 is a diode, 3, 3-1.3-2.4 is a phase comparison element, 5, 5
-1.5-2.5-3 is the first transmission line, 6, 6-1
．． 6-2.6-3 indicates the second transmission line. 'Shi, ＼ TOO＼

Claims (1)

[Claims] A reference signal is added to a diode (2) to generate a pulse synchronized with the reference signal, and the pulse and the sampled signal are added to a phase comparison element (3) to calculate the phase difference between the reference signal and the sampled signal. A first transmission line (5) connecting the diode (2) and the phase comparison element (3) in a sampling phase comparison circuit that obtains an output corresponding to
A sampling phase comparator circuit characterized in that a second transmission line (6) is connected between the ground and the ground.