JPH0155428B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a device for obtaining the phase of a fundamental signal from the phase angle of harmonics of the fundamental signal. An example of the use of the present invention is a specific radio navigation system (known as the Detsuka Navigation System), which has, for example, a main transmitter station and three slave transmitter stations, which are typically on the 6th and 5th frequencies, respectively, of the fundamental frequency. ,
Emit the 8th and 9th harmonics. Four signals are captured by the mobile receiver and various phase comparisons are made to display hyperbolic position lines, each having a master station and each slave station in its trajectory. For example, a mobile receiver compares the 6F signal from the master station with the 5F signal from each slave station at a frequency of 30F to obtain a phase angle representing a single hyperbolic position line, and the 6F signal from the master station at a frequency of 24F. Another position line can be obtained by comparing the 8F signals from each slave station. Although the position line representation is accurate, it is not unique and therefore typically requires additional phase comparisons at the fundamental frequency to obtain a coarser but less ambiguous position representation. Phase comparison suitable for eliminating ambiguity is known as route discrimination.
This interrupts the harmonically related signals that are normally radiated by the various stations in phase-locked synchronization, and these stations then radiate their associated harmonics, which in this example are 5F, 6F, 8F and 9FHz. Here 1F is the fundamental frequency. The combination of these harmonically related signals must provide a phase indication at the mobile receiver of the fundamental signal radiated by a particular station, and this phase angle is compared with the phase angle of the fundamental frequency effectively radiated by other stations. to provide the route identification. Various methods of combining available harmonic frequencies to reconstruct the phase angle of the fundamental frequency are known and have been in use for many years. However, because the propagation characteristics of different harmonic frequencies are different, the phase relationship between the transmitted harmonic frequencies is generally not guaranteed at the receiving point. This is particularly important since it is the phase relationship between the harmonics that determines the phase of the fundamental, not the phase of any one harmonic.
For example, if various phase angles are expressed as an integer fraction of 2π, the phase angle of the fundamental wave is 0.1 (2π) and the phase angles of the harmonics α ₅ , α ₆ , α ₈ and α ₉ are 0.5, 0.6, 0.8 and 0.8, respectively.
0.9, and if the phase angle α ₁ of the fundamental wave is 0.6 (2π), the phase angles are 0, 0.6, 0.8 and 0.4, respectively.
A particular harmonic does not determine the phase angle of the fundamental wave. Therefore, if one or two harmonics are phase-shifted differentially, an error will occur in the display of the phase angle of the fundamental frequency. This error can be minimized to improve the reconstruction of the fundamental wave phase obtained from the phase value of its harmonics in the presence of differential phase distortion, and also to improve the fundamental wave phase reconstruction when the fundamental signal phase is used for the above purpose. It is an object of the present invention to also provide improvements for use in other systems requiring such phase reconstruction of . It is also an object of the invention to use numerical processing rather than analog circuits for the reconstruction of the phase angle of the fundamental signal. For example, if the phase angle of the fundamental signal is 0.7 (2π) radians, ideally the 5th, 6th, 8th and 9th harmonics are 0.5 (2π), 0.2 (2π), 0.6 (2π) and
0.3
(2π), and it is convenient to regard the phase angle as a fraction, especially an integer, of the modulus 2π, which is a complete cycle of phase change. Even if the harmonics are not mixed or degraded, there is a general problem of obtaining the number 0.7 representing the phase at frequency 1F from a set of numbers (0.5, 0.2, 0.6, 0.3) by numerical processing. Therefore, it is also an object of the present invention to be able to reconstruct the phase of the fundamental wave from a numerical representation of the phase angles of a set of harmonics whose phase relationship indicates the phase of the fundamental wave. A device is described below that provides a fairly accurate representation of the fundamental wave despite the presence of approximately 0.1 (2π) radian phase error in each harmonic. As described below for specific embodiments, the present invention combines various combinations of numerical representations to a fundamental or a given harmonic frequency within a range that generally includes the fundamental and a given highest harmonic. Obtain a second numerical representation representing the phase angle of the frequency at which
It is based on converting at least one pair of these second representations into representations with the same modulus so that they represent the phase angle at the same frequency and merging the two representations. Typically, one of the two quadratic representations in each pair is converted to the same modulus as the other to give a more accurate representation of the fractional phase angle than the other representation, but this representation shows the integer value of the phase angle. . As will be explained below, the merging step is in effect forming a new numerical representation, which derives the integer value from the latter representation but the more accurate fractional value from the former representation. The merged value can be calculated as a quadratic representation to calculate a merged value representing the phase angle at different frequencies, or if desired, can be merged with one input numerical representation after appropriate multiplication. The purpose of this method is to effectively obtain fractional values of the phase at different frequencies between the fundamental and the highest harmonic using phase comparisons that can be made at a variety of different frequencies obtained by a simple combination of input frequencies. , to obtain an integer value of the phase angle at high frequencies using a numerical representation of the phase comparison at low harmonics. The representation of the phase angle at the higher frequency is then divided by the appropriate harmonic number to give multiple representations of the phase angle at the fundamental frequency, and from the average value of the resulting numerical representations the phase angle of the fundamental can be determined with a high degree of confidence. can be determined in degrees. Various processors are possible to obtain the required phase representation, preferably but not necessarily a programmed microprocessor. The program that can be formulated will depend on the specific harmonics available and the desired range of processing and information optimization of the highly redundant numerical display if the propagation is ideal; it will vary between the fundamental and the lowest received harmonic. can be obtained by a number of comparisons made at harmonic frequencies. FIG. 1 shows, for example, a part of the receiver of the phase comparison radio navigation device. The 9F, 8F, 5F and 6F signals received at inputs 1, 2, 3 and 4 are first radiated in phase locked synchronization and then radiated from each transmitting station at the appropriate time. These signals are connected to each comparator 1
1, 21, 31 and 41 into square signals, which are sequentially selected by the channel selector 6. The selector responds to the first arrival of a square wave positive transition of the selected harmonic frequency after selection activation. Details of each part of the comparator 11 and channel selector 10 are shown in FIG. 1D. The channel selection decoder 61 is connected to the comparator 1 via the buffer amplifier 62.
Bistable multivibrator 6 receiving the output of 1
Control 3. The bistable multivibrator 63 is one of the OR circuits 64 common to various channels.
Provides a signal to the input. A stable 12 MHz clock signal is received at input 5 and fed to a counter 7 adapted to divide by 3000, the positive edge of the selected waveform being used to strobe this counter. The numerical value obtained in this way is determined by the latch circuit 8.
The values are latched onto 12 lines and sent to random access memory 9 after being processed at each harmonic number. a central processing unit, which may be an M6800 microprocessor 10 as the other main element of the device;
A decoder/display device 11 and a programmable read-only memory ROM 12 are included. These are the various buffers shown in Figure 1.
It is used with gates, counters and monostable circuits to execute the programs shown in FIGS. 2 and 3, which will not be described in detail. FIG. 2 is a flowchart for reconstructing the phase of the fundamental wave from a numerical representation of the phase angle of the available harmonic signal, hereinafter referred to as the primary representation. FIG. 3 is a supplementary flowchart for the merge function used in the flowchart of FIG. The flowchart is illustrative and follows the process used and the multiple comparisons it makes. Essentially, the program is based on various merging of two numerical representations. One of these two numerical displays later in the program can be a primary display, but generally one is a combination of a plurality of primary displays and the other is a merged display. The two numerical displays show the phase angle at different frequencies, and the displays showing the phase angle at lower frequencies are multiplied so that there are two displays showing the phase angle at the same frequency, one of which is more accurate than the other. Although fractional values of the phase angle are shown, typically only one representation shows an integer value of the phase angle. The merged representation resulting from the merging of two representations has a more accurate decimal value than the integer value indicated by one representation and the other integer value determines. However, integer values are required because, after further merging, the merged representation must be divided by the harmonic number to obtain an representation of the phase angle at the fundamental frequency. It is desirable to obtain an average value of the phase angle of the fundamental wave from a representation of the phase angle of a large number of fundamental waves. The available primary representations φ ₅ , φ ₆ , φ ₈ and φ ₉ are the measured and stored phase angles of the input signal at frequencies of 5F, 6F, 8F and 9F, respectively, from which the phase of the 1F signal is obtained. Assume that there is no. In the first operation according to the flowchart of FIG.
The next representation φ ₅ is subtracted from the first order representation φ ₆ to produce a numerical representation of the phase at the "beat" frequency, in this case the fundamental frequency. This phase angle value does not take into account the contribution to the fundamental phase angle from φ ₈ and φ ₉ . The value of (φ ₆ −φ ₅ ) is essentially a decimal number. (θ ₁ )
The value obtained by _multiplying . The value of another phase angle of the second harmonic is expressed as (φ ₆ −φ ₅ +φ ₉ −φ ₆ ) by the combination of all four first-order representations. 1 of all 4
This representation using the following representation yields a decimal value between 0 and 2. This value (θ ₂ ) is a better estimate of the phase angle at the second harmonic, and dividing by 2 gives a correct representation of the phase angle of the fundamental. The other assumptions are less accurate assumptions of the phase of the second harmonic, but have the advantage of containing the required integer. The two assumed values are merged by taking the integer part of the assumed value giving the integer and fractional parts from the other assumed value. The resulting merged representation is divided by 2 to give an indication of the phase angle, but is further merged with other numerical representations of the phase angle at other frequencies to further merge the correct integer value with the more accurate decimal value. It is desirable to use it to give a clear indication. Multiplying the merged representation ψ ₂ ' already obtained in this way by 3/2 yields a number (ψ ₃ ) in the range 0 to 3, which is the first integer of the phase of the third harmonic of the fundamental and Indicates a decimal value. Only the second fractional value (θ ₃ ) of the phase of the third harmonic can be obtained from the representation of (φ ₆ +φ ₅ −φ ₈ ). The merging operation gives the second assumption and a fractional value (ψ ₃ ') representing the integer value, which, apart from possible significant digits, is the exact integer value obtained by the first step. To obtain a first assumed value of the phase angle at the fourth harmonic 4F, multiply by the last mentioned combined expression 4/3 to obtain a number (ψ ₄ ) in the range 0 to 4. This is merged with a second assumed value (θ ₄ ) representing only the fractional part obtained from the representation of (2φ ₆ −φ ₈ ). The resulting merged representation is multiplied by 3/2 to obtain the first assumed value ψ ₆ ′, which is the sixth harmonic
Contains the integer and fractional parts of the phase angle at 6F. This expected value is within the range of 0 and 6. The 6th harmonic is obtained at the input, so the first assumed value obtained by the previous merging is the 1st order numerical representation φ ₆ (=θ)
to obtain the best guess values for integers and decimals in the range 0 and 6. Divide this value by the harmonic number (6) to get ψ ₁₍₆₎ , that is, the first 1 of the phase angle of the fundamental wave.
You can get a display of . The remaining stages of the comparison multiply this assumed value by 5, 8, and 9, respectively, and merge the resulting representations with the respective primary representations φ ₅ , φ ₈ , and φ ₉ to obtain the 5th, 8th, and 9th harmonics. Expected values including integers and decimals of the phase angle are obtained, and these expected values are divided into 5 and 8, respectively.
and divided by 9 to give three more possible values of the phase angle at the fundamental frequency. Finally, the four available assumptions are combined and divided by four to obtain the average value of the fundamental phase angle. where _φo is the phase angle (but fractional) of the nF receiver channel, _θo is the phase angle (but fractional) of nF calculated from _φ1 to _φo , _ψo is _θ1 and the merged representation ψ Represents an integer ( ) and a fraction calculated from ₂ ′ to φ _o ′. Next, the merging function will be explained based on FIG. What is being done here is what is written in Table 1 as merging, and as you can see from Table 1, the inputs are ψ _o (integer I ₁ and decimal F ₁ ) and θ _o (decimal
F ₂ only) (e.g. ψ ₂ ′, ψ ³ ′, ψ ₄ ′, ψ ₆ ′) or ψ _o
(integers and decimals) and φ _o (decimal F ₂ only) (e.g. ψ ₅ ′,
ψ ₈ ′, ψ ₉ ′). First, compare F ₁ and F ₂ , and if the difference is more than ±0.5, multiply by 1 to keep it within ±0.5.
(This is the operation of I=I ₁ -1 or I=I ₁ +1.) However, if the result goes outside one cycle of the fundamental wave, in order to return to that one cycle, I is When negative, add n (I ₂ = I + n), I≧
When n, subtract n (I ₂ = I-n) and get the new I ₂ +
Get _F2 . This becomes ψ _o ′.

【table】

[Table] The table shows various numerical examples of the operation of the apparatus described with respect to FIGS. 1 to 3. In the first example, values of 0.5, 0.2, 0.6 and 0.3 are used for the fourth harmonic phase angle. As can be seen from the table, the phase value obtained is an exact value of 0.7. In the second example, the harmonic phase values change somewhat for the 5th, 8th, and 9th harmonics, but for the 6th harmonic.
Same as before for harmonics. Despite the error of 0.1 (2π) radians in each of the three harmonic signals changed, the error in the final value is only 0.02 (2π) radians. Assume that in the fourth example the 5th, 8th and 9th harmonics are the same as in the second example, but the 6th harmonic is significantly degraded. The final value obtained is 0.33, which is unexpected in practice but consistent, and the value of 0.33 (2π) for the fundamental was chosen for the phase value in the fourth example.
0.66, 0, instead of the values 0.6, 0, 0.7 and 0.2
Corresponds to values of 0.67 and 0. The third example shows a constrained example in which the phase angle of the sixth harmonic is degraded by 36 degrees. This gives a final phase angle of 0.34 or 0.7, an undesirable result. This indicates that a particular program is more sensitive to the phase error of the 6th harmonic than to the phase error of other harmonics, and uses the merged representation for the 6th harmonic to calculate the final assumed value for the other harmonics. This is a phenomenon that occurred as a result of obtaining .

[Brief explanation of drawings]

Fig. 1 is a diagram showing the connection arrangement relationships of Fig. 1A, Fig. 1B, and Fig. 1C, and Fig. 1A, Fig. 1B, and Fig. 1C are partial circuits constituting a part of the receiver of the radio navigation device, respectively. Figure 1D is a partial detailed circuit diagram of Figure 1A, Figure 2 is a diagram showing the connection arrangement relationship of Figures 2A and 2B, and Figures 2A and 2B are each a diagram of the microprocessor program. Partial Diagrams Constituting a Flow Chart FIG. 3 is a flow diagram of a portion of a microprocessor program. Explanation of symbols, 6...Channel selector, 7...
Counter, 8...Latch circuit, 9...RAM, 1
0...Microprocessor, 11...Decoder/
Display, 12...ROM.

Claims (1)

[Claims] 1. A first signal numerically representing the phase angle of a lower harmonic of the fundamental frequency and a phase angle within one cycle of a phase change at the frequency of a higher harmonic of the fundamental frequency. in a device for generating a signal numerically representing a phase angle at a fundamental frequency from a second signal numerically representing (ii) forming a merged signal comprising said integer and a second signal; (iii) said merged signal; A signal generating device configured such that a signal is divided by a harmonic number of said higher order harmonic. 2. A device for obtaining the phase of a fundamental signal from harmonics of a plurality of fundamental signals, the set of principal numerical displays representing the fractional phase angle of each harmonic, i.e. the phase angle within one cycle of phase change at each frequency. In the apparatus for converting the harmonics into
Each numerical representation represents a phase angle at a different frequency, in which at least one of said representations (θ ₃ )
One is a combination of multiple main displays (for example, φ ₆ + φ ₅
-φ ₈ ), and the other is another such combination or merged representation (ψ ₂ ′), and in each merge the numerical representations of the phase angle at low frequencies of said different frequencies are multiplied. Represents the phase angle (ψ ₃ ) at the same frequency as other numerical displays, and the result of merging (ψ ₃ ′)
is a phase angle display consisting of an integer part of the multiplication display and a fractional part of the other display, where the integer part represents the phase change of an integer cycle,
The fractional part represents the phase angle within one cycle phase change, forming at least one final merging of the main representation (φ ₆ ) with each value obtained from the previous merging at successively higher frequencies, said final merging Said device, characterized in that it gives an indication of the fundamental phase angle (ψ ₁₍₆₎ ) by dividing the indication (ψ ₆ ′) obtained by (ψ 6 ′) by the respective harmonic number (6). .