CA1052870A - Electronic signal processing system - Google Patents
Electronic signal processing systemInfo
- Publication number
- CA1052870A CA1052870A CA257,689A CA257689A CA1052870A CA 1052870 A CA1052870 A CA 1052870A CA 257689 A CA257689 A CA 257689A CA 1052870 A CA1052870 A CA 1052870A
- Authority
- CA
- Canada
- Prior art keywords
- signal
- processing system
- input
- signal processing
- amplitude
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000012545 processing Methods 0.000 title claims abstract description 35
- 238000012935 Averaging Methods 0.000 claims abstract description 7
- 238000010586 diagram Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000003990 capacitor Substances 0.000 description 2
- 230000010363 phase shift Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 230000008901 benefit Effects 0.000 description 1
- JJWKPURADFRFRB-UHFFFAOYSA-N carbonyl sulfide Chemical compound O=C=S JJWKPURADFRFRB-UHFFFAOYSA-N 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 238000012886 linear function Methods 0.000 description 1
- 230000005055 memory storage Effects 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
- H03L5/00—Automatic control of voltage, current, or power
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
- G01S3/02—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using radio waves
- G01S3/14—Systems for determining direction or deviation from predetermined direction
- G01S3/143—Systems for determining direction or deviation from predetermined direction by vectorial combination of signals derived from differently oriented antennae
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
- G01S3/02—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using radio waves
- G01S3/14—Systems for determining direction or deviation from predetermined direction
- G01S3/16—Systems for determining direction or deviation from predetermined direction using amplitude comparison of signals derived sequentially from receiving antennas or antenna systems having differently-oriented directivity characteristics or from an antenna system having periodically-varied orientation of directivity characteristic
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
- H03L7/00—Automatic control of frequency or phase; Synchronisation
- H03L7/06—Automatic control of frequency or phase; Synchronisation using a reference signal applied to a frequency- or phase-locked loop
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Disclosed is an electronic signal processing system for an alterna-ting voltage input signal. A phase-locked loop network has an input adapted to receive the signal and produce an intermediate signal comprising a sub-stantially noise free sine wave with a phase equal to the average phase of the input signal. The intermediate signal is applied to an input of a vari-able gain amplifier which produces an output signal proportional to the in-termediate signal, and an amplitude averaging loop network has the input signal and the output signal as its inputs and produces a biasing signal which is applied to a control input of the variable gain amplifier to maintain the output signal equal in amplitude to the average amplitude of said input signal.
The system can be used in a Wattson-Watt type radio direction finder to eliminate noise.
Disclosed is an electronic signal processing system for an alterna-ting voltage input signal. A phase-locked loop network has an input adapted to receive the signal and produce an intermediate signal comprising a sub-stantially noise free sine wave with a phase equal to the average phase of the input signal. The intermediate signal is applied to an input of a vari-able gain amplifier which produces an output signal proportional to the in-termediate signal, and an amplitude averaging loop network has the input signal and the output signal as its inputs and produces a biasing signal which is applied to a control input of the variable gain amplifier to maintain the output signal equal in amplitude to the average amplitude of said input signal.
The system can be used in a Wattson-Watt type radio direction finder to eliminate noise.
Description
~.o5'~t37 ELECTRONIC SIGNAL PROCESSING SYSTEM
This invention relates to an electronic signal processing system which generates a substantially noise free sine wave of ampli-tude and phase equal to the average amplitude and phase of an input alternating signal.
The types of noise or distortion which the present signal processing system eliminates or reduces include random (white) noise, pulse interference~ amplitude and frequency modulation, and phase jitter. Various types of electronic devices, including frequency domain filters, have been constructed for the reduction of some or all of the aforementioned undesirable characteristics found in transmitted electronic signals. The present invention operates on an entirely dif-ferent principle than such frequency domain filters.
The present invention replaces an input signal by the output of a sine wave generator. The output signal has a phase equal to the average phase of the input signal, and an amplitude equal to the average amplitude of the input signal, over a controlled sampling period. The output signal is constructed by a voltage controlled oscillator (VCO). The output of the VCO is sampled and compared with the input signal in phase, and any phase difference is detected, averaged, and applied as a bias to the VCO ao as to reduce this difference to a minimum. This is commonly known as a phase-locked loop network. In addition, a variable gain ampli-fier is provided for the VCO output and the output of this amplifier is now compared in amplitude with that of the original input signal. Any ampli-tude difference is averaged and amplified and applied to control the gain of the variable gain amplifier so as to reduce the difference to a minimum. The amplitude comparison loop network must not be confused with an automatic gain control ~AGC) circuit which is designed to give constant output. In the present invention, the amplitude of the output lOS'~870 signal of the electronic signal processing system is made equal to the average amplitude of the input signal, sampled over a specific time frame.
According to the present invention there is provided an electronic signal processing system for an alternating voltage input signal comprising a phase-locked loop network having an input adapted to receive said signal and produce an intermediate signal comprising a substantially noise free sine wave with a phase equal to the average phase of said input signal, said intermediate signal being applied to an input of a variable gain amplifier which produces an output signal proportional to said intermediate signal, and an amplitude averaging loop network having said input signal and said output signal as its inputs which produces a biasing signal which is applied to a control input of said variable gain amplifier to maintain said output signal equal in amplitude to the average amplitude of said input signal.
The present invention will now be described with the aid of the accompan~ drawings, in which:
Figure l is a block diagram of an electronic signal processing system according to the invention;
Figure 2 is a block diagram showing an application of the present invention in a three channel radio direction finder system;
Figure 3 is a block diagram showing the present invention used in another three channel radio direction finding system.
In Figure l, the signal input is applied to terminal El from where it passes to an amplifier limiter AL which raises its amplitude to a conven-ient handling level and also eliminates any amplitude modulation. In the presence of a signal, a 50% duty ratio square wave is available at the output lO of the amplifier limiter. The voltage controlled oscillator (VC0) is preset near the input frequency by means of tuning capacitor Cl. A square wave VCO output 12 and the output of the amplifier-limiter lO are now applied as inputs to the phase comparator 14, which is essentially an 105;~8~0 OR gate, wherein the output of the OR gate is now a linear function of the phase difference of the two inputs. The phase comparator output 15 is now applied to the voltage tuning element of the VCO via an integrating ne~work, shown as the combination of Rl and C2. The time constant of the integrating network detern~ines the time over which the phase-locked network averages the phase difference. It also defines the speed of response of the phase-lock.
A sine wave output 16 of the VCO is applied to the variable gain amplifier A2, the output 17 of which constitutes the output of the signal processing system at terminal E2. The system output and input are now compared in a differential operational amplifier A3. Any amplitude difference is detected by the detector U and averaged with a time constant of R3 C3 The averaged amplitude difference is fed to a control input 18 of the variable gain amplifier A2 to maintain the out-put signal at E2 at a predetermined level.
For optimum dynamic operation of the signal processing system, the amplitude feedback time constant R3 C3 and the phase-lock time con-stant Rl C2 should be made equal. Both time constants can be made selectable by means of ganged switches Sl and S2. Resistor R2 provides a preset adjustment of the gain of amplifier A2 to bring it within the range of control. Amplifiers A2 and A3 must not show any appreciable phase shift at the operating frequency.
The signal processing system can operate at an output frequency which is a multiple or sub-multiple of the input frequency, and with an output voltage which is a multiple or sub-multiple of the input voltage.
In the first case, a frequency scaler must be added in the link from the VCO output to the phase comparator which is shown dotted as X in Figure 1. The second condition obtains when a voltage divider or multiplier is added in the output sampling line of the amplitude comparator, shown in the dotted block labelled Z in Figure 1.
~05'~870 One particular application of the signal processing system relates to the three channel Wattson-Watt type of radio direction finder. It is generally known that the Wattson-Watt direction finder 50 (Figure 2) comprises three identical receiver channels 23, 24, and 25, each tuned to the same fre-quency and adjusted to present as near as possible, equal gains and phase shifts. The outputs of the three channels 30, 31 and 32 are applied to the vertical 38 and horizontal 37 deflection and the brightness control 36 of a cathode ray tube indicator 35 in such a way as to display a radial bearing trace indicating the angle of arrival of the radio signal. It is known that, as the radio signal becomes weaker, the background noise will blur the bearing trace, making it difficult for the operator to read the bearing angle. As much as 15 dB signal to noise ratio may be necessary for a clean display.
Such an application is depicted in Figure 2.
In Figure 2, three identicial signal processing systems 20, 21 and 22 are inserted between the end of each receiver channel 23, 24 and 25 and the respective input of the cathode ray tube bearing indicator at 30, 31 and 32 as shown. The signal processing systems each work at the final intermediate frequency, but are independent of each other, each automatically adjusting itself so that it does not introduce any gain or phase difference in the chan-nel in which it operates. By virtue of their noise reduction properties, thesignal processing systems in the present application enable a clean trace to be shown even if the signal to noise ratio is substantially reduced. In the net effect, the radio direction finder 50 employing these signal pro-cessing systems is made more sensitive and can effectively be used over an increased distance. This improvement is independent of the sensitivity of the direction finding antenna 40, 41, 42 used with the system and is also independent at the atmospheric or cosmic noise as long as the latter two are of random ~white noise) nature.
Insertion of the signal processing systems in the Wattson-Watt three channel radio direction finder does not impair its value of indi-lOS'~870 cating local reradiation and of being capable of indicating directionof two or more signals within the pass-band of the associated receiver.
In the respective cases the random noise blur is eliminated, leaving a clear ellipse or parallelogram, or a combination of both. In this appli-cation, the time constants of the three noise filters are made equal and are adjusted according to the nature of the noise and of the signal so as to eliminate the noise as far as possible while retaining adequate speed of response. Such a time constant may be selected by means of a switch to be operated manually or automatically with other controls.
In this radio direction finder, it is often expedient to com-mutate two of the receiver channels periodically in order to examine the accuracy of the channel balance. Two different bearings are shown alter-natively if an unbalance exists. In a known method the two bearings are compared and the gain and balance adjustments are operated until the difference is reduced to zero. With the signal processing system installed in all three channels, it is possible to increase the time constant of noise averaging until it becomes much longer than the commutation period.
In this way the output of each signal processing system will indicate the average gain and phase of the commutated channels. This application substantially eliminates the need for channel balancing, manual or auto-matic, so long as a reasonable balance is present in the receiver so that linear approximations are valid for sine and cosine functions of the bearing angle.
Figure 3 depicts another application related to Wattson-Watt type radio direction finding circuits. The system in Figure 2 can be simplified to that appearing in Figure 3. The three channel DF antenna 40, 41 and 42, the commutation switches 51 and 52 and the signal processing systems 20, 21 and 22 feeding to a cathode ray tube bearing indicator are retained, but only a single channel receiver 55 is used in place of the three channels.
The receiver is periodically switched into each channel in the 1-2-3 sequence _5_ 105'~87(~
providing synchronising pulses ln turn to each of the signal processing sys-tem oscillators. The time constant of each signal processing system is set large enough to maintain the frequency and amplitude of oscillation constant over the commutation gap. In this way the gain and phase matched three channel receiver can be replaced by a single channel receiver of communication type at a great saving in cost. The price to pay for this simplification is the long time constant of the signal processing system which means that bearings cannot be taken on signals of very short duration or while scanning the frequency spectrum.
This application for use with a single channel receiver must not be confused with a known method, also for a single channel receiver, which makes use of charging a capacitor to the amplitude of channel voltage but has no memory storage for its phase. The present signal processing system stores both amplitude and phase information and its application retains full advantage of the Wattson-Watt method without the costly matched receivers.
While the present invention has been described with respect to the details of the various illustrated embodiments depicted, changes and variations will occur to those skilled in the art on reading the description, and such can obviously be made without departing from the scope of the present invention.
This invention relates to an electronic signal processing system which generates a substantially noise free sine wave of ampli-tude and phase equal to the average amplitude and phase of an input alternating signal.
The types of noise or distortion which the present signal processing system eliminates or reduces include random (white) noise, pulse interference~ amplitude and frequency modulation, and phase jitter. Various types of electronic devices, including frequency domain filters, have been constructed for the reduction of some or all of the aforementioned undesirable characteristics found in transmitted electronic signals. The present invention operates on an entirely dif-ferent principle than such frequency domain filters.
The present invention replaces an input signal by the output of a sine wave generator. The output signal has a phase equal to the average phase of the input signal, and an amplitude equal to the average amplitude of the input signal, over a controlled sampling period. The output signal is constructed by a voltage controlled oscillator (VCO). The output of the VCO is sampled and compared with the input signal in phase, and any phase difference is detected, averaged, and applied as a bias to the VCO ao as to reduce this difference to a minimum. This is commonly known as a phase-locked loop network. In addition, a variable gain ampli-fier is provided for the VCO output and the output of this amplifier is now compared in amplitude with that of the original input signal. Any ampli-tude difference is averaged and amplified and applied to control the gain of the variable gain amplifier so as to reduce the difference to a minimum. The amplitude comparison loop network must not be confused with an automatic gain control ~AGC) circuit which is designed to give constant output. In the present invention, the amplitude of the output lOS'~870 signal of the electronic signal processing system is made equal to the average amplitude of the input signal, sampled over a specific time frame.
According to the present invention there is provided an electronic signal processing system for an alternating voltage input signal comprising a phase-locked loop network having an input adapted to receive said signal and produce an intermediate signal comprising a substantially noise free sine wave with a phase equal to the average phase of said input signal, said intermediate signal being applied to an input of a variable gain amplifier which produces an output signal proportional to said intermediate signal, and an amplitude averaging loop network having said input signal and said output signal as its inputs which produces a biasing signal which is applied to a control input of said variable gain amplifier to maintain said output signal equal in amplitude to the average amplitude of said input signal.
The present invention will now be described with the aid of the accompan~ drawings, in which:
Figure l is a block diagram of an electronic signal processing system according to the invention;
Figure 2 is a block diagram showing an application of the present invention in a three channel radio direction finder system;
Figure 3 is a block diagram showing the present invention used in another three channel radio direction finding system.
In Figure l, the signal input is applied to terminal El from where it passes to an amplifier limiter AL which raises its amplitude to a conven-ient handling level and also eliminates any amplitude modulation. In the presence of a signal, a 50% duty ratio square wave is available at the output lO of the amplifier limiter. The voltage controlled oscillator (VC0) is preset near the input frequency by means of tuning capacitor Cl. A square wave VCO output 12 and the output of the amplifier-limiter lO are now applied as inputs to the phase comparator 14, which is essentially an 105;~8~0 OR gate, wherein the output of the OR gate is now a linear function of the phase difference of the two inputs. The phase comparator output 15 is now applied to the voltage tuning element of the VCO via an integrating ne~work, shown as the combination of Rl and C2. The time constant of the integrating network detern~ines the time over which the phase-locked network averages the phase difference. It also defines the speed of response of the phase-lock.
A sine wave output 16 of the VCO is applied to the variable gain amplifier A2, the output 17 of which constitutes the output of the signal processing system at terminal E2. The system output and input are now compared in a differential operational amplifier A3. Any amplitude difference is detected by the detector U and averaged with a time constant of R3 C3 The averaged amplitude difference is fed to a control input 18 of the variable gain amplifier A2 to maintain the out-put signal at E2 at a predetermined level.
For optimum dynamic operation of the signal processing system, the amplitude feedback time constant R3 C3 and the phase-lock time con-stant Rl C2 should be made equal. Both time constants can be made selectable by means of ganged switches Sl and S2. Resistor R2 provides a preset adjustment of the gain of amplifier A2 to bring it within the range of control. Amplifiers A2 and A3 must not show any appreciable phase shift at the operating frequency.
The signal processing system can operate at an output frequency which is a multiple or sub-multiple of the input frequency, and with an output voltage which is a multiple or sub-multiple of the input voltage.
In the first case, a frequency scaler must be added in the link from the VCO output to the phase comparator which is shown dotted as X in Figure 1. The second condition obtains when a voltage divider or multiplier is added in the output sampling line of the amplitude comparator, shown in the dotted block labelled Z in Figure 1.
~05'~870 One particular application of the signal processing system relates to the three channel Wattson-Watt type of radio direction finder. It is generally known that the Wattson-Watt direction finder 50 (Figure 2) comprises three identical receiver channels 23, 24, and 25, each tuned to the same fre-quency and adjusted to present as near as possible, equal gains and phase shifts. The outputs of the three channels 30, 31 and 32 are applied to the vertical 38 and horizontal 37 deflection and the brightness control 36 of a cathode ray tube indicator 35 in such a way as to display a radial bearing trace indicating the angle of arrival of the radio signal. It is known that, as the radio signal becomes weaker, the background noise will blur the bearing trace, making it difficult for the operator to read the bearing angle. As much as 15 dB signal to noise ratio may be necessary for a clean display.
Such an application is depicted in Figure 2.
In Figure 2, three identicial signal processing systems 20, 21 and 22 are inserted between the end of each receiver channel 23, 24 and 25 and the respective input of the cathode ray tube bearing indicator at 30, 31 and 32 as shown. The signal processing systems each work at the final intermediate frequency, but are independent of each other, each automatically adjusting itself so that it does not introduce any gain or phase difference in the chan-nel in which it operates. By virtue of their noise reduction properties, thesignal processing systems in the present application enable a clean trace to be shown even if the signal to noise ratio is substantially reduced. In the net effect, the radio direction finder 50 employing these signal pro-cessing systems is made more sensitive and can effectively be used over an increased distance. This improvement is independent of the sensitivity of the direction finding antenna 40, 41, 42 used with the system and is also independent at the atmospheric or cosmic noise as long as the latter two are of random ~white noise) nature.
Insertion of the signal processing systems in the Wattson-Watt three channel radio direction finder does not impair its value of indi-lOS'~870 cating local reradiation and of being capable of indicating directionof two or more signals within the pass-band of the associated receiver.
In the respective cases the random noise blur is eliminated, leaving a clear ellipse or parallelogram, or a combination of both. In this appli-cation, the time constants of the three noise filters are made equal and are adjusted according to the nature of the noise and of the signal so as to eliminate the noise as far as possible while retaining adequate speed of response. Such a time constant may be selected by means of a switch to be operated manually or automatically with other controls.
In this radio direction finder, it is often expedient to com-mutate two of the receiver channels periodically in order to examine the accuracy of the channel balance. Two different bearings are shown alter-natively if an unbalance exists. In a known method the two bearings are compared and the gain and balance adjustments are operated until the difference is reduced to zero. With the signal processing system installed in all three channels, it is possible to increase the time constant of noise averaging until it becomes much longer than the commutation period.
In this way the output of each signal processing system will indicate the average gain and phase of the commutated channels. This application substantially eliminates the need for channel balancing, manual or auto-matic, so long as a reasonable balance is present in the receiver so that linear approximations are valid for sine and cosine functions of the bearing angle.
Figure 3 depicts another application related to Wattson-Watt type radio direction finding circuits. The system in Figure 2 can be simplified to that appearing in Figure 3. The three channel DF antenna 40, 41 and 42, the commutation switches 51 and 52 and the signal processing systems 20, 21 and 22 feeding to a cathode ray tube bearing indicator are retained, but only a single channel receiver 55 is used in place of the three channels.
The receiver is periodically switched into each channel in the 1-2-3 sequence _5_ 105'~87(~
providing synchronising pulses ln turn to each of the signal processing sys-tem oscillators. The time constant of each signal processing system is set large enough to maintain the frequency and amplitude of oscillation constant over the commutation gap. In this way the gain and phase matched three channel receiver can be replaced by a single channel receiver of communication type at a great saving in cost. The price to pay for this simplification is the long time constant of the signal processing system which means that bearings cannot be taken on signals of very short duration or while scanning the frequency spectrum.
This application for use with a single channel receiver must not be confused with a known method, also for a single channel receiver, which makes use of charging a capacitor to the amplitude of channel voltage but has no memory storage for its phase. The present signal processing system stores both amplitude and phase information and its application retains full advantage of the Wattson-Watt method without the costly matched receivers.
While the present invention has been described with respect to the details of the various illustrated embodiments depicted, changes and variations will occur to those skilled in the art on reading the description, and such can obviously be made without departing from the scope of the present invention.
Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An electronic signal processing system for an alternating voltage input signal comprising a phase-locked loop network having an input adapted to receive said signal and produce an intermediate signal comprising a sub-stantially noise free sine wave with a phase equal to the average phase of said input signal, said intermediate signal being applied to an input of a variable gain amplifier which produces an output signal proportional to said intermediate signal, and an amplitude averaging loop network having said input signal and said output signal as its inputs which produces a biasing signal which is applied to a control input of said variable gain amplifier to maintain said output signal equal in amplitude to the average amplitude of said input signal.
2. The electronic signal processing system according to claim 1 wherein said phase-locked loop network contains a frequency scaling circuit such that the output signal has a frequency proportional to said input signal.
3. The electronic signal processing system according to claim 1 wherein said amplitude averaging loop network contains a voltage scaling circuit such that the amplitude of the output signal is proportional to that of said input signal.
4. An electronic signal processing system according to claim 2 or 3 wherein both the frequency of the output signal and the amplitude of the output signal are proportional to that of the said input signal.
5. The electronic signal processing system according to claim 1 in combination with a Wattson-Watt type radio direction finder having a three channel receiver and a cathode ray tube bearing indicator wherein said signal processing systems are inserted between the output of each receiver channel and the respective inputs of a cathode ray tube bearing indicator.
6. The combination of claim 5 in which the Wattson-Watt type radio direction finder has its receiver channels commutated, wherein the time averaging constant of the signal processing system is longer than said commutation period, such that said signal processing system indicates the average gain and phase of the commutated channels.
7. The electronic signal processing system according to claim 1 in combination with a Wattson-Watt radio direction finder having a single channel receiver commutated between three channels, said signal processing system being connected between the output of said single channel receiver and the inputs to a cathode ray tube indicator, said single processing systems having a time averaging constant longer than the commutation gap of the single channel receiver.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA257,689A CA1052870A (en) | 1976-07-23 | 1976-07-23 | Electronic signal processing system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA257,689A CA1052870A (en) | 1976-07-23 | 1976-07-23 | Electronic signal processing system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1052870A true CA1052870A (en) | 1979-04-17 |
Family
ID=4106495
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA257,689A Expired CA1052870A (en) | 1976-07-23 | 1976-07-23 | Electronic signal processing system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1052870A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1986000998A1 (en) * | 1984-07-27 | 1986-02-13 | Selenia Spazio | Antenna tracking system using sequential lobing |
-
1976
- 1976-07-23 CA CA257,689A patent/CA1052870A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1986000998A1 (en) * | 1984-07-27 | 1986-02-13 | Selenia Spazio | Antenna tracking system using sequential lobing |
| US4963890A (en) * | 1984-07-27 | 1990-10-16 | Selenia Spazio S.P.A. | Antenna tracking system using sequential lobing |
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