JPS5851233B2 - VOR reference phase signal and synchronization signal generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a VOR device, and more particularly to a reference phase signal and synchronization signal generating device.

VOR (V HF) has traditionally been one of the navigational aid facilities.
0mn1 Range) device is used.

In other words, as is well known, this VOR device operates at 30Hz.
The azimuth of the reception point is determined by phase comparison between the FM signal (reference phase signal) and the 30 Hz AM signal (variable phase signal) having a phase corresponding to the reception azimuth.

Therefore, the 30Hz FM in the conventional VOR device
As shown in FIG. 1, the signal is generated as follows by a tone wheel 14 mechanically connected to a goniometer 13 for generating a 30 Hz AM signal.

That is, this tone wheel 14 is formed with 332 protrusions, and as the tone wheel 14 is rotated, the pickup coil 15 to which the protrusions are fixed is fixed.
induces a voltage in

Here, since the mechanical arrangement of the protrusions is taken into consideration to obtain a modulation index of 16 necessary for a 30Hz FM signal, the tone wheel 14 is set to 1 in synchronization with the goniometer 13.
9960±48 by rotating at 80 rpm
An FM signal (reference phase signal) of 0 Hz can be obtained.

However, in such a (30 Hz) FM signal generation system, the two output frequencies of the 30 Hz AM signal (variable phase signal) and the 30 Hz FM signal (reference phase signal) are driven by the rotational drive of the goniometer 13 and tone wheel 14. It is directly affected by the rotational characteristics of the synchronous motor 12 serving as the source, that is, the power input frequency of the synchronous motor 12.

For this reason, an AC stabilized power supply 11 that operates stably is required, and since a rotating machine is used, there are drawbacks such as increased distortion of the output waveform due to the influence of vibrations and the like.

Further, since the mutual phase relationship between the 30 Hz AM signal and the 30 Hz FM signal is determined by the mechanical axis coupling relationship between the goniometer 13 and the tone wheel 14, it is extremely difficult to adjust the mutual phase relationship.

Furthermore, since such an FM signal generation method has many mechanical elements, there are various drawbacks such as a significant decrease in stability due to aging.

On the other hand, recently it has become possible to non-mechanically generate a 30 Hz AM signal (variable phase signal) using a so-called electronic goniometer, and from this point as well, it has become possible to eliminate the above drawbacks and generate a 30 Hz FM signal (reference phase signal). ) and a variable phase signal generated by an electronic gonio to easily adjust the phase relationship.

The present invention has been made in view of the above points, and an object of the present invention is to provide a VOR reference phase signal and synchronization signal generating device that digitally generates an FM signal.

First, the principle of the reference phase signal (FM signal) generator according to the present invention will be briefly explained. Generally, the periodic function F(ωt
) is the center frequency of the carrier wave to be modulated by f.

When the modulation index is M, the periodic function F(ωt
) is divided into n, the frequencies f1t...fn of the frequency-modulated carrier waves at that time are expressed as follows.

Therefore, it is necessary to divide one period of the periodic function F(ωt) into n, and switch the frequency of the carrier wave to f1 to fn in the above equations (1) to (n) every time J il r J t2...Jtn. An FM signal (reference phase signal) is obtained digitally.

Next, one embodiment of the present invention will be described in detail with reference to FIGS. 2 and 3.

FIG. 2 is a circuit configuration diagram showing one embodiment of the VOR reference phase signal and synchronization signal generating device according to the present invention;
The figure shows one period of a sine wave 5in2π・301 -90'~2
3 is an output signal waveform diagram of each part of the device shown in FIG. 2 in the range of 700. FIG.

That is, in this case, one period of a periodic function of a sine wave 5in2π·30t is divided into 120 equal parts, and the carrier wave frequency f1. f
2...f12o (9960-480H2~Every Sec)
The samples are sequentially sampled.

In Figure 2, 26 is 30Hz (modulated wave component) and 996
0Hz (carrier component) and a common multiple of the frequency required by the goniometer, as high as possible, for example 10.368 (
It is a clock pulse generator such as a crystal oscillator that stably oscillates a clock selected at 10.36836 MHz, which is actually 10.36836 MHz, but is determined by considering the accuracy of the crystal oscillator.

The clock from this clock pulse generator 26 is guided to a counter 27 and counted.

The output of each bit of the counter 2γ is sent to the decoder 28.
guided by.

Here, the decoder 28 has the frequency f1 of the carrier wave divided into 120 equal parts. f2. ...f1□.

In this case, from the properties of the sine wave, f1~-fao and f
6□～f1□.

In order to take advantage of the fact that they are correspondingly equal, that is, in this case, they are equal in 60 combinations, 60
Contains matching circuits.

Therefore, when the counter 27 counts the number of clocks shown below, coincidence pulses are sequentially supplied to the sampling circuit 29 from each coincidence circuit in the decoder 28.

1/2・1/f1・10.368X10'1/2-1/
fao”I O, 368
60+480Hz), the repetition frequency of each coincidence pulse output from the decoder 28 is 2 f1-2, f6 . (99604
80 Hz to 9960 + twice the frequency of 480 Hz).

On the other hand, the clock from the clock pulse generator 26 is also supplied to a counter 33, and the output of this counter 33 is a sampling pulse generator that generates a sampling pulse for sampling each coincident pulse from the decoder 28 in a sampling circuit 29. is supplied to the container 30.

That is, this sampling pulse generator 30 has, for example, 6
It is configured to include a 0-bit shift register, etc., and the counter 33 inputs the 180 degrees of the sine wave.
A set pulse (FIG. 3a) for setting every angle and a shift pulse for shifting every 3 degrees (FIG. 3b) are supplied.

As a result, the sampling pulse generator 30 divides the 180° of the sine wave into 60 equal parts and shifts them every 3°, so that, for example, each output terminal for each bit is A1. A2...
・If it is A6o, then in the direction of A1 → A6o at -900 to 900 of the sine wave, and A at 900 to 2700
Sampling pulses (FIG. 3d) which are sequentially shifted in the direction I from 6o to A1 are generated and supplied to the sampling circuit 29.

In this case, normal rotation and reversal of the shift direction are performed based on the 180° gate output (FIG. 3C) obtained from the aforementioned set pulse.

Here, the sampling circuit 29 receives, for example, each coincidence pulse from the decoder 28 and A1→A6o or A6 from the sampling pulse generator 30 at each input terminal.
In this case, it consists of 60 two-man NAND circuits to which each sampling pulse shifted in the o→A1 direction is applied, and a NOR circuit to which the output of each NAND circuit is supplied.

Therefore, as a result, each coincidence pulse from the decoder 28 is sequentially sampled every 3 degrees of the sine wave, and the sampled pulses are supplied to the counter 27 as a reset pulse, and the frequency dividing circuit 31 and It is sent out from the output end via the filter 32.

That is, in this case, the counter 2γ is reset and the sampling output (FIG. 3f is , the FM signal (reference phase signal) whose repetition frequency is 9960±
Since the frequency is twice as high as 480 Hz, by resetting the counter 2γ at this period and counting down by the frequency dividing circuit 31 made of a flip-flop or the like, a square wave of 9960±480 Hz (
Figure 3g) is obtained, and this square wave is set to 9960±480 Hz.
A desired output signal of 9960±480 Hz, 30 Hz FM signal (reference phase signal) (FIG. 3h) is obtained by passing the signal through a filter 32 having a band of .

That is, the output signal obtained from the filter 32 (FIG. 3h) is a signal obtained by multiplying a 9960 Hz carrier wave by frequency modulation FM with a modulation index of 16 using a 30 Hz signal.

On the other hand, in order to synchronize the 30 Hz FM signal thus obtained and the output from the goniometer 34, that is, the 30 Hz AM signal (variable phase signal), with a constant phase relationship, each bit output of the counter 33 and the digital Each bit of the switch 35 is matched by a comparator 36, and a synchronization signal having a constant phase relationship corresponding to the FM signal and the set value of the digital switch 35 is supplied to the goniometer 34.

Therefore, according to the present invention as described above, the stability of the reference phase signal obtained by digitally generating the signal is improved, compared to the conventional method in which the signal is generated by a synchronous motor. Furthermore, the synchronization signal obtained in conjunction with the reference phase signal makes it extremely easy to adjust the phase relationship between the reference phase signal and the variable phase signal. Since the present invention does not include any external elements, it is possible to provide an extremely good VOR reference phase signal and synchronization signal generating device that can improve reliability.

Note that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a 30Hz FM signal generation system in a conventional VOR device, Fig. 2 is a circuit block diagram showing an embodiment of a VOR reference phase signal and synchronization signal generating device according to the present invention, and Fig. 3 a- h is an output signal waveform diagram of each part explaining the operation of the apparatus shown in FIG. 2; 26... Clock pulse generator, 27, 33.
... Counter, 28 ... Decoder, 29
... Sampling circuit, 3o... Song sampling pulse generator, 3F... Frequency dividing circuit, 32... Song filter, 34... Song coniometer, 35...
Digital switch, comparator. 6

Claims (1)

[Claims] 1. In a VOR device that determines the direction of the reception point by comparing the phase of a variable phase signal having a phase corresponding to the reception direction with a reference phase signal, frequency modulation is performed on a carrier wave that provides a desired reference phase signal and the carrier wave. means for generating a clock pulse having a frequency that is a common multiple of each frequency with the periodic function; first and second counting means for counting the clock pulses by the means; and the periodic function taken by the first counting means. The frequency f1 of the frequency-modulated carrier wave when one period is divided into n. means for generating a coincidence pulse for each specified count value corresponding to each cycle of f2...fn; and generating sampling pulses at a desired rate in correspondence with the division number n based on the output of the second counting means. means for sampling the coincident pulse using a sampling pulse produced by the means; means for frequency-dividing the sampling output by the means by a predetermined frequency; and waveform shaping of the frequency-divided output by the means to have a predetermined band characteristic. means for deriving said desired reference phase signal by said second
means for deriving a synchronization signal for synchronizing the reference phase signal and the variable phase signal with a constant phase relationship by matching the output of the counting means and the output from the digital phase value setting means; 1. A VOR reference phase signal and synchronization signal generator, comprising: