WO2000028657A9 - Adjustable balanced modulator - Google Patents
Adjustable balanced modulatorInfo
- Publication number
- WO2000028657A9 WO2000028657A9 PCT/US1999/026306 US9926306W WO0028657A9 WO 2000028657 A9 WO2000028657 A9 WO 2000028657A9 US 9926306 W US9926306 W US 9926306W WO 0028657 A9 WO0028657 A9 WO 0028657A9
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- signal
- modulator
- phase
- local oscillator
- linear device
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/16—Circuits
- H04B1/26—Circuits for superheterodyne receivers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
- H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
- H03D7/14—Balanced arrangements
- H03D7/1425—Balanced arrangements with transistors
- H03D7/1441—Balanced arrangements with transistors using field-effect transistors
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
- H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
- H03D7/14—Balanced arrangements
- H03D7/1425—Balanced arrangements with transistors
- H03D7/1458—Double balanced arrangements, i.e. where both input signals are differential
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
- H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
- H03D7/14—Balanced arrangements
- H03D7/1425—Balanced arrangements with transistors
- H03D7/1491—Arrangements to linearise a transconductance stage of a mixer arrangement
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
- H03D2200/00—Indexing scheme relating to details of demodulation or transference of modulation from one carrier to another covered by H03D
- H03D2200/0001—Circuit elements of demodulators
- H03D2200/0023—Balun circuits
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
- H03D2200/00—Indexing scheme relating to details of demodulation or transference of modulation from one carrier to another covered by H03D
- H03D2200/0041—Functional aspects of demodulators
- H03D2200/0043—Bias and operating point
Definitions
- the present invention relates to the field of communications, and more particularly to balanced modulators.
- Modulation in the context of communications, can be described as the process of encoding source data onto a carrier frequency.
- Mixers can be used for modulators to translate a baseband signal to an RF frequency band, and mixers can be used as product detectors to translate RF signals to baseband in a demodulator.
- a mixer performs a multiplication function on the two signals, the band limited RF input signal N ⁇ t) and a local oscillator N L o(t)- Mixers are typically classified as being unbalanced, single balanced or double balanced.
- a single balanced mixer (ideally) has feedthrough for only one of the inputs.
- a double balanced mixer (ideally) has feedthrough from neither of the input signals .
- the adjustable balanced modulator of the present invention overcomes the disadvantages and drawbacks of known modulators by providing both a unique structure of the modulator and by providing several ways to adjust the modulator to improve its performance.
- the adjustable balanced modulator modulates two input signals, including a local oscillator signal, and an RF input signal.
- the RF input signal can be a band limited signal centered at (or modulated onto) a carrier frequency f c .
- a phase inverter receives a local oscillator (LO) signal at a frequency f LO and produces a first (in-phase) LO signal and a second (out-of-phase) LO signal.
- the adjustable balanced modulator also includes first and second non-linear devices.
- the first non-linear device receives the RF input signal (e.g., centered at afrequency f c ) and the in-phase LO signal (at a frequency f LO ) to produce a first mixed signal.
- the second non-linear device receives the RF input signal and the out-of-phase LO signal to produce a second mixed signal.
- a summer sums the two mixed signals to produce an output signal including two intermodulation products (product terms, including a sum term and a difference term).
- the performance of the balanced modulator is improved by using an adjustable phase corrector and/or adjustable bias voltages.
- An adjustable phase corrector can be used to maintain the RF input signals substantially in-phase to provide greater suppression of one of the input signals (e.g., the LO signal and/or the RF input signal).
- Bias voltages are used to bias the non-linear devices to operate in a substantially linear region (e.g., to prevent unwanted harmonics in the output signal) and can be used to equalize the levels of the sum and difference product terms output from the modulator. In this manner, modulator performance is significantly improved.
- Fig. 1 is a block diagram of an adjustable balanced modulator according to an embodiment of the present invention.
- Fig. 2 is a diagram illustrating a spectral content of an output signal of an adjustable balanced modulator according to an embodiment of the present invention.
- Fig. 3 is a flow chart illustrating operation of an adjustable balanced modulator according to an embodiment of the present invention.
- Fig. 4 is a block diagram illustrating an adjustable balanced modulator according to another embodiment of the present invention.
- Fig. 5 is a schematic diagram illustrating an adjustable balanced modulator according to yet another embodiment of the present invention.
- Fig. 6 is a block diagram illustrating a transmitter system according to an embodiment of the present invention.
- Fig. 1 is a block diagram of the adjustable balanced modulator according to an embodiment of the present invention.
- An adjustable modulator 100 operates to generate a modulated output Nout(t) signal based on two input signals: an RF input signal and a local oscillator.
- Modulator 100 includes a phase inverter 102 for generating a phase shifted signal, first and second non-linear devices each receiving two input signals and outputting a mixed signal, a phase corrector for equalizing phases of a signal and a summer 150 for summing the two signals output from the first and second non-linear devices.
- Modulator 100 receives two input signals.
- An RF input source 108 provides a band-limited RF input signal, which may be centered around a carrier frequency f c .
- the RF input signal may be an information signal modulated onto a carrier f c .
- the second input signal is a local oscillator (LO) signal N L o(t)- Modulator 100 includes a phase inverter 102 which receives a first local oscillator (LO) signal (at a frequency f LO ) via line 101 and outputs the first LO signal on line 104 and (a second LO signal) a phase shifted version of the first LO signal, also at a frequency of f LO on line 106.
- the phase shifted LO signal on line 106 is approximately 180 degrees out of phase from the LO signal online 104.
- Phaseinverter 102 can be, for example, a transformer, an operational amplifier (op amp), a transistor, or the like.
- Balanced modulator 100 includes first and second non-linear devices.
- the first and second non-linear devices are implemented as a first transistor Ql and a second transistor Q2, respectively.
- Transistors Ql and Q2 canbe, for example, field effect transistors (FETs).
- FETs field effect transistors
- the transistors Q 1 and Q2 are double- gate FETs.
- Other types of non-linear devices can be used, such as operational amplifiers, differential transistors, etc.
- the non-linear devices can advantageously include some degree of adjustability to allow performance of the balanced modulator to be fine-tuned or adjusted, as described below.
- First transistor Ql includes a source terminal (s) 110, a drain terminal (d) 112, a first gate terminal (G 1 ) 114 and a second gate terminal (G2) 116.
- Source terminal 110 is connected to ground.
- Second gate terminal 116 receives the in-phase LO signal via line 104.
- a first bias voltage (Biasl) is also coupled to the second gate terminal 116 to bias the first transistor Q 1 to operate in a substantially linear operating region.
- the RF input signal (e.g., centered at a carrier frequency f c ) is output onto two paths, including lines 120 and 122.
- the RF input signal is coupled to the first gate terminal 114 via line 120.
- a first capacitor Cl is connected between line 120 .and ground.
- Second transistor Q2 includes a source terminal (s) 130, a drain terminal (d) 132, a first gate terminal (Gl) 134 and a second gate terminal (G2) 136.
- Source terminal 130 is connected to ground.
- Second gate terminal 136 receives the out-of-phase LO signal via line 106.
- a second bias voltage (Bias2) is also coupled to the second gate terminal 136 to bias the second transistor Q2 to operate in a substantially linear operating region.
- the RF input signal is coupled to the first gate terminal 134 via line 122.
- a second capacitor C2 is connected between line 122 and ground.
- a third common bias voltage (B ias3 ) is connected in common via lines 120 and
- Bias3 can be a negative voltage for further placing transistors Ql and Q2 in an optimal linear operating region.
- the lengths of lines 120 and 122 can be approximately the same length to keep the RF input signals on both lines 120 and 122 in-phase (as indicated by the double hash marks on lines 120 and 122). Because it is difficult for lines 120 and 122 to be exactly the same length, however, the two RF input signals input to the transistors Ql and Q2 will typically be slightly out of phase. When the phases of the input signals are different (out-of-phase), this limits or decreases the suppression of the original RF input signal in the output of the balanced modulator 100. Therefore, to better suppress one of the input signals (in this case, the RF input signal), the present invention advantageously provides an adjustable phase corrector for correcting or equalizing the phases of the RF input signals on lines 120 and 122.
- phase correctors can be used.
- the phase corrector includes first and second capacitors C 1 and C2.
- capacitors C 1 and C2 are adjustable to fine tune and equalize the phases of the signals in lines 120 and 122.
- capacitor C2 is shown as being adjustable, although, C 1 may also be adjustable.
- C 1 (the fixed capacitor) can be chosen to be 1 to 2 pf, and Cl can be 1/2 of the range of C2 (the variable capacitor). More generally, the fixed capacitor can be 1/2 the maximum value of the variable capacitor.
- Transistor Ql produces a first mixed output signal onto line 140 that includes one or more input signals, including the RF input signal V m (t) and the in-phase local oscillator signal N LO (t) which can be fed through, and a sum term, [N in (t) (centered at carrier frequency f c ) + N L o(t) (at frequency f LO )].
- the sum term results from the fact that the LO is in phase with the RF input, causing the two signals to be added together.
- the first mixed output signal likely will not include any additional harmonics, such as second harmonics (2f c +f LO ), third harmonics, fourth harmonics, etc.
- Q 1 outputs a signal on line 140 including the sum term at a frequency f c + f LO , the RF input signal at a frequency of f c and the LO signal at a frequency of f LO .
- transistor Q2 produces a second mixed output signal onto line 142 that includes one or more input signals, including the RF input signal Ni n (t) and the out- of-phase local oscillator signal V LO (t) which can be fed through, and a difference term [Ni n ( - N L o(t)]- The difference term is caused by the LO signal being 180 degrees out of phase creating a subtraction of the LO signal. Because transistor Q2 preferably operates in the linear region, the second mixed output signal likely will not include any additional harmonics.
- Q2 outputs a signal on line 142 including the difference term at a frequency of f c - f LO , the RF input signal at a frequency f c and the LO signal at a frequency of f LO
- a summer 150 receives the first mixed signal via line 140 and the second mixed signal via line 142, and sums these two signals to produce an output signal provided on line 152.
- Summer 150 can be, for example, a differential summer, a differential amplifier or a transformer where the inputs are added 180 degrees out of phase.
- Both Ql and Q2 outputs an RF input term at a frequency of f c .
- the output on line 152 includes at least the sum and difference product terms, with the RF input signal suppressed (due to cancellation of the 2 RF input terms) if the phase corrector is properly adjusted.
- the RF input signal can be suppressed 40dB or more as compared to the product terms.
- the output signal can also include the local oscillator (LO) signal, or the modulator 100 can suppress the LO signal. Therefore, the adjustable balanced modulator 100 can be either a single balanced modulator or a double balanced modulator.
- summer 150 will inherently suppress the LO signal as well.
- a bandpass filter can be connected to the output 152 of modulator 100 to filter out or remove the LO signal from the output signal.
- many antenna systems will not transmit a signal less than, for example, 600 MHz.
- aLO signal is outside the frequency response of the antenna system, such an LO signal will not be transmitted (e.g., LO signal is effectively suppressed by the antenna).
- two adjustable balanced modulators 100 can be combined in parallel to form an adjustable double balanced modulator to also suppress the LO signal.
- the outputs of both the modulators 100 would be input into an additional summer (e.g., transformer) to generate the output signal of the double balanced modulator, where the double balanced modulator output includes only product terms, while suppressing the RF input signal and the LO signal.
- an additional summer e.g., transformer
- the inputs illustrated in Fig. 1 may be switched. That is, the RF input signal (modulated onto the carrier signal) may be input to the phase inverter 102, and source 108 would be a local oscillator (LO) source.
- LO local oscillator
- Fig. 2 is a diagram illustrating the spectral content of the output signal of the balanced modulator 100 according to an embodiment of the present invention.
- the output signal on line 152 includes two product terms, including a sum term 210 located at a frequency f c +f L o > and a difference term 206 located at a frequency fc-f , where f c is the carrier frequency of the original RF input signal N in (t) and f LO is the frequency of the local oscillator.
- the output signal may also include the original LO signal 204 at f LO (or, the LO may be suppressed).
- a dashed line in Fig. 2 indicates that the RF input signal 208 is suppressed by modulator 100 (particularly, when the phase corrector C2 is properly adjusted).
- f c it is not necessary for f c to be greater than f LO - Rather, f LO can be greater than f c
- the adjustable bias voltages, Biasl and Bias2 bias the transistors by adjusting the drain currents of transistors Ql and Q2, respectively, to operate in a linear region.
- the bias voltages can be further adjusted (preferably within the linear operating range of transistors Ql and Q2) to set the amplitudes or levels of sum term 210 and the difference term 206 of the output signal (Fig. 2) to predetermined levels.
- Biasl affects the amplitude of one of the terms (sum or difference terms), while Bias2 affects the amplitude of the other term.
- Biasl affects the amplitude of the sum term
- Bias2 affects the amplitude of the difference term.
- the best performance of balanced modulator 100 occurs when the RF input (at the carrier frequency) is fully suppressed and the levels or amplitudes of the sum and difference terms are equalized.
- the phases of the RF input signals input to Ql and Q2 should be balanced or equalized (e.g., by adjusting the phase corrector, Cl and/or C2) and the levels of the sum and difference terms 210 and 206, respectively (Fig.2), of the output signal should be matched or equalized (e.g., by properly adjusting the values of the bias voltages, Biasl and Bias2).
- the balanced modulator 100 of the present invention allows the adjustment of the RF input signal phases to improve RF input (and carrier) suppression and allows adjustment of the non-linear devices (e.g., by adjusting the bias voltages of the transistors) to equalize the levels of the output product terms, and thereby improve significantly upon the performance of existing mixers or modulators.
- Fig. 3 is a flow chart illustrating the operation of the adjustable balanced modulator of the present invention.
- a first LO signal is received.
- a second LO signal is generated that is 180 degrees out of phase with the first LO signal.
- an RF input signal is received.
- the RF input signal is split into two paths (e.g., lines 120 and 122, Fig. 1). The phases of the RF input signals on the two paths are corrected or adjusted to be in-phase.
- a first mixed signal is generated by, for example, pumping a first nonlinear device using the in-phase local oscillator signal and the phase corrected RF input signal.
- a second mixed signal is generated by, for example, pumping a second non-linear device using the out-of-phase local oscillator signal and the phase corrected RF input signal.
- the first and second mixed signals are summed to generate an output signal including sum and difference terms and having a substantially suppressed RF input signal.
- the non-linear devices are adjusted or biased to set the levels of the output product terms (sum and difference terms) to predetermined levels. According to an embodiment of the present invention, the bias voltages are adjusted to equalize the levels of the sum and difference terms.
- Fig. 4 is a block diagram illustrating an adjustable balanced modulator 400 according to another embodiment of the present invention.
- the embodiment of Fig. 4 is similar to that in Fig. 1, but is more general than Fig. 1.
- a phase inverter 402 receives a local oscillator signal and produces a first (in-phase) local oscillator (LO) signal on line 404 and a second local oscillator (LO) signal on line 406 that is 180 degrees out of phase with the first LO signal.
- An RF input source 424 supplies an RF input signal on lines 420 and 422.
- the adjustable balanced modulator 400 includes a first non-linear device 410 and a second non-linear device 412.
- a phase corrector 414 can be used to adjust or correct the RF input signals on lines 420 and 422 to be substantially in-phase.
- First non-linear device 410 is pumped by the in-phase LO signal via line 404 and the phase corrected RF input signal via line 420 and produces a first mixed signal on line 440.
- Second non-linear device 412 is pumped by the out-of-phase LO signal received via line 406 and the phase corrected RF input signal received via line 422 and produces a second mixed signal on line 442.
- a summer 450 sums the first and second mixed signals received via lines 440 and 442 to produce an output signal including product terms and where the RF input signal is suppressed.
- Use of the phase corrector 414 to equalize the phases of the RF input signals greatly improves the suppression of the RF input signal.
- the first non-linear device 410 is adjusted or biased by a first bias voltage (Bias 1 ) supplied via line 417 to operate in a substantially linear region
- the second non-linear device 412 is adjusted or biased by a second bias voltage (Bias2) supplied via line 419 to operate in a substantially linear region.
- Bias 1 and Bias2 can be further adjusted to set the levels or amplitudes of the sum and difference terms in the output signal to predetermined levels.
- Fig. 5 is a schematic diagram of an adjustable balanced modulator 500 according to another embodiment of the present invention.
- a local oscillator source 505 provides a local oscillator signal to a transformer Tl .
- Transformer Tl operates as a phase inverter to generate an in-phase version of the LO signal (indicated by the dot) on the left path 510, and a 180 degree out-of phase version of the LO signal on the right path 512.
- An RF input source 515 provides an RF input signal.
- the RF input signal can be an input signal that is amplitude modulated (double-sideband- suppressed carrier modulation) onto a carrier frequency of 800 MHz, while the local oscillator (LO) signal can be provided at 40 MHz. Other frequencies, however, can be used.
- Transistors Ql and Q2 operate as non-linear devices (but are biased to operate in the substantially linear region).
- a first adjustable bias voltage (Biasl) is provided to the second gate terminal (G2) of Ql. Biasl can be adjusted (to set the operating point of Q 1 and to set the levels of a corresponding output product term) by using a first potentiometerPl, which is connected between 1.25 V and -2.5 V.
- a second potentiometer P2 is used to provide a second adjustable bias voltage Bias2 to the second gate terminal (G2) of Q2, and includes the same alternative upper and lower voltages as PI .
- Bias2 sets the operating point of Q2 and also sets the level or amplitude of a corresponding output product term.
- a third bias voltage (Bias3) is connected in common to the first gate terminals (Gl ) of Q 1 and Q2 to further set the operating point of Ql and Q2 in the linear region.
- Adjustable capacitor Cl is connected to the first gate Gl of transistor Ql and operates as a phase corrector by allowing the phase of the RF input signal input to Ql be adjusted to be substantially in-phase with the RF input signal input to Q2.
- Transistor Ql generates a first mixed signal via line 540.
- Transistor Q2 produces a second mixed signal via line 542.
- a second transformer T2 operates as a differential summer to sum the two mixed signals received via lines 540 and 542, and outputs a signal having sum and difference terms with substantially matching amplitudes or levels (based on the adjustment of the bias voltages), and a substantially suppressed RF input signal based on the balancing of the phases of the RF input signals using the phase corrector (C 1 ).
- transformer Tl can be a transformer part number RFTM- 1 A available from RF Prime Co.
- transformer T2 can be a 4:1 transformer part number ETC 4-1-2 from MA/COM, Inc.
- Other transformers can be used as well.
- the adjustable balanced modulator of the present invention canbe used in-a communications system to modulate an information signal and rotational frequency signal as described in detail in copending application serial no. 09/064,525, filed on April 23, 1998 entitled “Communications System,” (the "copending application”).
- the intermodulation products described above are referred to generically as "sidebands" in the copending application.
- a communications channel is defined at least in part by an electromagnetic wave having a carrier frequency and an electric (E) field vector.
- the extremity or terminus of the E field vector traces a non- linear periodic path at a rotation frequency less that the carrier frequency and greater than zero from the perspective of an observer looking into the axis of propagation of the wave.
- the combination of the rotation frequency (defining a particular periodic path of the terminus of the E field vector) and the carrier frequency define a communications channel.
- the information signal is modulated onto a carrier frequency. Any suitable rotation frequency can be selected that is greater than one-half of the bandwidth of the information signal and less than the carrier frequency. For example, according to an embodiment of the present invention, a rotation frequency can be chosen that is 1/30th of the carrier frequency.
- the adjustable balanced modulator of the present invention can be used to modulate the modulated information signal and the rotation frequency signal.
- the local oscillator (LO) signal is replaced in Fig. 1 by the rotation frequency signal, and the RF input signal is replaced by the modulated information signal.
- the balanced modulator 100 then outputs a signal including substantially balanced sum and difference terms (based on the adjustment of the bias voltages of the non-linear devices), while the original modulated information signal (including carrier signal) is substantially suppressed (based on the adjustment of the phase corrector.)
- the modulator of the present invention can be used the system of co-pending application serial no. 09/064,525 in place of the balanced mixer modulator 104 (Fig. 2), and/or in place of voltage variable attenuator 142 (Fig. 5), and/or as a component within nonlinear periodic path modulator 506 (Fig. 15) and/or as a component within the nonlinear periodic path demodulator 518 (Fig. 15).
- Fig. 6 is a block diagram of a transmitter system 600 according to an embodiment of the present invention.
- a rotation frequency signal is received via line 602. Three different phase shifted versions of the rotation freqeuency signal are required according to this embodiment of the present invention.
- the rotation frequency signal is input to phase shifters 604 and 606.
- Phase shifter 606 shifts the rotation frequency signal by 120 degrees to generate a 120 degree phase shifted rotation frequency signal onto line 610.
- Phase shifter 604 shifts the rotation frequency signal 240 degrees to output a 240 degree phase shifted rotation frequency signal onto line 608.
- Transmitter system 600 also includes three adjustable balanced modulators 612, 614 and 616, each of which may be the same as modulators 100, 400 or 500 according to embodiments of the present invention.
- Modulator 616 modulates the unshifted rotation frequency signal received via line 602 and a modulated information signal received via line 615, and outputs a signal on line 622.
- an information signal is modulated (e.g., amplitude, frequency or phase modulated) onto a carrier frequency signal to generate the modulated information signal that is provided on lines 611, 613 and 615 which are input to modulators 612, 614 and 616.
- Modulator 614 modulates the 120 degree shifted rotation frequency signal received via line 610 and the modulated information signal received via line 613, and outputs a signal on line 620.
- Modulator 612 modulates the 240 degree shifted rotation frequency signal received via line 608 and the modulated information signal received via line 611, and outputs a signal on line 618.
- Modulators 612, 614 and 616 are coupled via lines 618, 620 and 622 to an antenna system 617 including antenna elements 630, 632 and 634, respectively.
- Antenna elements 630, 632 and 634 may be monopoles, dipoles, or other antenna elements.
- the bias voltages and phase correctors of modulators 612, 614 and 616 are properly adjusted so that each modulator outputs a signal that includes substantially equalized sum and difference intermodulation product terms and a suppressed modulated information signal (including a suppressed carrier frequency signal).
- the output signals are then output to antenna elements 630, 632 and 634.
- Each antenna element 630, 632 and 634 radiates an individual electromagnetic (EM) wave.
- the individual EM waves radiated or transmitted from each antenna element 630, 632 and 634 superpose to create a resultant EM wave.
- the terminus of the Electric (E) field vector of the resultant EM wave rotates about the axis of propagation at a rate equal to the rotation frequency signal. (Note that the resultant EM wave "rotates" about the axis of propagation in a very specific sense with respect to a rosette pattern, as described in detail in the copending application).
- the combination of the rotation frequency (defining a particular periodic path of the terminus of the E field vector) and the carrier frequency define a communications channel.
- One channel system including a group of two phase shifters 604 and 606 and a group of three modulators 612, 614 and 616 (illustrated in Fig. 6), provide the transmission signals for one channel, where the channel is defined by the frequency of the rotation frequency signal and the carrier frequency of the modulated information signal.
- Each additional channel is defined by a unique combination of carrier frequency and rotation frequency.
- a separate channel system including a separate group of two phase shifters and three modulators are provided for each separate channel.
- Each channel system receives a rotation frequency signal and a modulated information signal (at a carrier frequency), where the combination of rotation frequency and carrier frequency is unique for each channel transmitted over antenna system 617.
- the modulators of each channel system receiving a zero shifted rotation frequency signal are coupled to a first common antenna element 634.
- the modulators of each channel system receiving a 120 degree phase shifted rotation frequency signal are coupled to a second common antenna element 632.
- the modulators of each channel system receiving a 240 degree phase shifted rotation frequency signal are coupled to a third common antenna element 630.
- the number of modulators per channel corresponds to the number of antenna elements.
- adjustable balanced modulator of the present invention can be used in the dual carrier embodiment disclosed in the copending application.
- the adjustable balanced modulator of the present invention can be used as the amplitude modulators 246 and 248 in Fig. 12 of the copending application.
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Transmitters (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU16111/00A AU1611100A (en) | 1998-11-09 | 1999-11-09 | Adjustable balanced modulator |
EP99958825A EP1145422A4 (en) | 1998-11-09 | 1999-11-09 | Adjustable balanced modulator |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US18821698A | 1998-11-09 | 1998-11-09 | |
US09/188,216 | 1998-11-09 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2000028657A1 WO2000028657A1 (en) | 2000-05-18 |
WO2000028657A9 true WO2000028657A9 (en) | 2000-09-28 |
Family
ID=22692220
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1999/026306 WO2000028657A1 (en) | 1998-11-09 | 1999-11-09 | Adjustable balanced modulator |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP1145422A4 (en) |
AU (1) | AU1611100A (en) |
WO (1) | WO2000028657A1 (en) |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4308473A (en) * | 1978-05-24 | 1981-12-29 | Raytheon Company | Polyphase coded mixer |
US4475088A (en) * | 1981-06-04 | 1984-10-02 | Westinghouse Electric Corp. | Gain imbalance corrected quadrature phase detector |
JPS59127432A (en) * | 1983-01-11 | 1984-07-23 | Oki Electric Ind Co Ltd | Mixer circuit |
US4658440A (en) * | 1984-07-27 | 1987-04-14 | Texas Instruments Incorporated | Single balanced self-oscillating dual gate FET mixer |
US5153469A (en) * | 1991-04-25 | 1992-10-06 | Rockwell International Corporation | Biasing network for use with field effect transistor ring mixer |
FI96072C (en) * | 1991-08-27 | 1996-04-25 | Nokia Mobile Phones Ltd | Modulator phase adjustment |
JPH08125446A (en) * | 1994-10-25 | 1996-05-17 | Nec Corp | Microwave modulator, mixer and its characteristic adjustment method |
US5826183A (en) * | 1997-03-05 | 1998-10-20 | Samsung Electronics Co., Ltd. | Circuit for simultaneous frequency doubler and mixer |
-
1999
- 1999-11-09 AU AU16111/00A patent/AU1611100A/en not_active Abandoned
- 1999-11-09 EP EP99958825A patent/EP1145422A4/en not_active Withdrawn
- 1999-11-09 WO PCT/US1999/026306 patent/WO2000028657A1/en not_active Application Discontinuation
Also Published As
Publication number | Publication date |
---|---|
EP1145422A4 (en) | 2002-10-02 |
AU1611100A (en) | 2000-05-29 |
WO2000028657A1 (en) | 2000-05-18 |
EP1145422A1 (en) | 2001-10-17 |
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