WO2007053425A1 - Filtre passe-bande complexe - Google Patents

Filtre passe-bande complexe Download PDF

Info

Publication number
WO2007053425A1
WO2007053425A1 PCT/US2006/041844 US2006041844W WO2007053425A1 WO 2007053425 A1 WO2007053425 A1 WO 2007053425A1 US 2006041844 W US2006041844 W US 2006041844W WO 2007053425 A1 WO2007053425 A1 WO 2007053425A1
Authority
WO
WIPO (PCT)
Prior art keywords
pass filter
band
voltage
transconductors
pll
Prior art date
Application number
PCT/US2006/041844
Other languages
English (en)
Inventor
Emmanuel Marais
Original Assignee
Atmel Corporation
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from FR0511160A external-priority patent/FR2892872B1/fr
Application filed by Atmel Corporation filed Critical Atmel Corporation
Publication of WO2007053425A1 publication Critical patent/WO2007053425A1/fr

Links

Classifications

    • 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
    • H03L7/08—Details of the phase-locked loop
    • H03L7/099—Details of the phase-locked loop concerning mainly the controlled oscillator of the loop
    • H03L7/0995—Details of the phase-locked loop concerning mainly the controlled oscillator of the loop the oscillator comprising a ring oscillator
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H11/00—Networks using active elements
    • H03H11/02—Multiple-port networks
    • H03H11/04—Frequency selective two-port networks
    • H03H11/0422—Frequency selective two-port networks using transconductance amplifiers, e.g. gmC filters
    • H03H11/0444—Simulation of ladder networks
    • H03H11/045—Leapfrog structures
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H11/00—Networks using active elements
    • H03H11/02—Multiple-port networks
    • H03H11/04—Frequency selective two-port networks
    • H03H11/08—Frequency selective two-port networks using gyrators
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J1/00—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general
    • H03J1/0008—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor
    • H03J1/0041—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor for frequency synthesis with counters or frequency dividers
    • H03J1/005—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor for frequency synthesis with counters or frequency dividers in a loop
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J3/00—Continuous tuning
    • H03J3/02—Details
    • H03J3/06—Arrangements for obtaining constant bandwidth or gain throughout tuning range or ranges
    • 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
    • H03L7/08—Details of the phase-locked loop
    • H03L7/0805—Details of the phase-locked loop the loop being adapted to provide an additional control signal for use outside the loop
    • 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
    • H03L7/08—Details of the phase-locked loop
    • H03L7/085—Details of the phase-locked loop concerning mainly the frequency- or phase-detection arrangement including the filtering or amplification of its output signal
    • H03L7/089—Details of the phase-locked loop concerning mainly the frequency- or phase-detection arrangement including the filtering or amplification of its output signal the phase or frequency detector generating up-down pulses
    • H03L7/0891—Details of the phase-locked loop concerning mainly the frequency- or phase-detection arrangement including the filtering or amplification of its output signal the phase or frequency detector generating up-down pulses the up-down pulses controlling source and sink current generators, e.g. a charge pump
    • 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
    • H03L7/08—Details of the phase-locked loop
    • H03L7/085—Details of the phase-locked loop concerning mainly the frequency- or phase-detection arrangement including the filtering or amplification of its output signal
    • H03L7/089—Details of the phase-locked loop concerning mainly the frequency- or phase-detection arrangement including the filtering or amplification of its output signal the phase or frequency detector generating up-down pulses
    • H03L7/0891—Details of the phase-locked loop concerning mainly the frequency- or phase-detection arrangement including the filtering or amplification of its output signal the phase or frequency detector generating up-down pulses the up-down pulses controlling source and sink current generators, e.g. a charge pump
    • H03L7/0895—Details of the current generators
    • H03L7/0896—Details of the current generators the current generators being controlled by differential up-down pulses
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H11/00—Networks using active elements
    • H03H11/02—Multiple-port networks
    • H03H11/04—Frequency selective two-port networks
    • H03H2011/0494—Complex filters

Definitions

  • the present invention relates to electronics, and more particularly to a complex band-pass filter.
  • Band-pass filters are well known. Band-pass filters are commonly used in communication systems, where high-frequency signals are down converted and often demodulated into low frequency signals. A well-suited architecture is typically chosen depending on the input bandwidth, adjacent channels, and requested sensitivity and selectivity of the system implementing the band-pass filter.
  • band-pass filters are made from conventional transconductors, which typically include differential pairs of transistors, and these band-pass filters are often tuned with a high-impedance bias voltage. Some other filters are tuned with a low- impedance source. For example, filters using the Nauta transconductor are tuned by changing their supply voltage.
  • a complex band-pass filter includes a band-pass filter coupled to a voltage source.
  • the band-pass filter includes a first plurality of transconductors that receives a first voltage, where the first voltage controls the center frequency of the band-pass filter.
  • the band-pass filter also includes a second plurality of transconductors, wherein the second plurality of transconductors receives a second voltage, where the second voltage controls the bandwidth of the band-pass filter.
  • the complex band-pass filter has automatic frequency tuning against process variations, a programmable center frequency, and a programmable bandwidth.
  • Figure 1 is a block diagram of a complex band-pass filter with automatic frequency tuning, in accordance with the present invention.
  • Figure 2 is a schematic diagram of a band-pass filter, which may be used to implement the band-pass filter of Figure 1, in accordance with the present invention.
  • Figure 4 is a schematic diagram of a differential channel, which can be used to implement each of the differential channels of Figure 2, in accordance with the present invention.
  • Figure 5 is a schematic diagram of a transconductor, which may be used to implement each of the transconductors of Figures 2 and 3.
  • Figure 6 is a schematic diagram of a passive low-pass filter, which represents the differential channel of Figure 4.
  • Figure 7 is a schematic diagram illustrating a complex transformation on internal nodes for the band-pass filter of Figure 2, in accordance with the present invention.
  • Figure 8 is a chart showing AC responses of the band-pass filter with respect to VFC changes, in accordance with the present invention.
  • Figure 9 is a chart showing AC responses of the band-pass filter with respect to
  • VB W changes, in accordance with the present invention.
  • Figure 10 is chart showing V CTRL , V FC , and V BW versus process variations when VFC and VBW are ratios of V C T R L, in accordance with the present invention.
  • Figure 11 is a block diagram showing a complex band-pass filter where the center frequency Fc and the bandwidth BW are programmable, in accordance with the present invention.
  • FIG 12 is a block diagram of an exemplary polyphase filter, in which the bandpass filter of Figure 2 may be implemented, in accordance with the present invention.
  • Figure 13 is a simulation schematic of the complex band-pass filter used to simulate the complex band-pass filter of Figure 11, in accordance with the present invention.
  • FIG 14 is a block diagram of a voltage controlled oscillator (VCO), which may be used to implement the VCO of Figures 1 and 11, in accordance with the present invention.
  • VCO voltage controlled oscillator
  • Figure 15 is a schematic diagram of a bias cell, which may be used to implement the bias cell of Figure 11, in accordance with the present invention.
  • FIG 16 is a block diagram of a PLL control cell, which may be used to implement the PDF, the charge pump (CP), and the loop filter of Figures 1 and 11, in accordance with the present invention.
  • FIG 17 is a schematic diagram of a PFD, which may be used to implement the PFD of Figures 1, 11, and 16, in accordance with the present invention.
  • Figure 18 is a schematic diagram of a CP, which may be used to implement the CP of Figures 1, 11, and 16, in accordance with the present invention.
  • Figure 19 is a schematic diagram of a loop filter, which may be used to implement the loop filter of Figures 1, 11, and 16, in accordance with the present invention.
  • FIG 20 is a schematic diagram of a VOC buffer, which may be used to implement the VOC buffer of Figures 1 and 11, in accordance with the present invention.
  • FIG 21 is a schematic diagram of FC and BW buffers, which may be used to implement the FC and BW buffers and of Figure 11, in accordance with the present invention.
  • Figure 22 is a schematic diagram of the decoder, which may be used to implement the decoder of Figure 21, in accordance with the present invention.
  • the present invention relates to electronics, and more particularly to a complex band-pass filter.
  • the following description is presented to enable one of ordinary skill in the art to make and use the invention, and is provided in the context of a patent application and its requirements.
  • Various modifications to the preferred embodiment and the generic principles and features described herein will be readily apparent to those skilled in the art.
  • the present invention is not intended to be limited to the embodiment shown, but is to be accorded the widest scope consistent with the principles and features described herein.
  • a complex band-pass filter includes a band-pass filter that has automatic frequency tuning.
  • the complex band-pass filter also has a programmable center frequency and a programmable bandwidth.
  • the complex band-pass filter also includes a phase locked loop and buffers that supply separate low-impedance voltages to the band-pass filter. One voltage programs the center frequency and the other voltage programs the bandwidth.
  • FIG 1 is a block diagram of a complex band-pass filter 100 with automatic frequency tuning, in accordance with the present invention.
  • the complex band-pass filter 100 includes a band-pass filter 110 and a phase locked loop (PLL) 112, which couples to a reference clock 114.
  • PLL 112 functions as a voltage source and outputs a control voltage V CTRL for the band-pass filter.
  • the PLL 112 includes a phase frequency detector (PFD) 120, a charge pump (CP) 122, a loop filter 124, a voltage controlled oscillator (VCO) buffer 126, and a VCO 128.
  • the band-pass filter 110 is a continuous time complex transconductance-C (gm-C) integrated filter using transconductors with low input impedance on their control signal.
  • the complex band-pass filter 100 utilizes the VCO buffer 126 and the VCO 128 in order to automatically tune the operating frequency of the band-pass filter 110. More specifically, the VCO buffer 126 supplies the control voltage V CTRL to the VCO 128 (and to the band-pass filter 110).
  • the VCO 128 has integrators that utilize transconductors and capacitors such that the time constant of the integrators is proportional to C/gm-diff.
  • the input impedance of the control voltage V C TRL is sufficiently high, like that of a metal oxide semiconductor (MOS) transistor gate to prevent stability problems in the loop filter 124.
  • the VCO buffer 126 does not disturb the stability of the PLL loop as long as its gain bandwidth product is sufficiently larger than the center frequency (Fc) of the band-pass filter 110.
  • the control voltage VC TR L may be directly provided by a supply voltage other than a PLL.
  • Figure 2 is a schematic diagram of a band-pass filter 200, which may be used to implement the band-pass filter 110 of Figure 1, in accordance with the present invention.
  • the band-pass filter 200 includes a group of transconductors 202 that is adapted to receive a voltage V B W- The voltage V B W controls the bandwidth of the band-pass filter 200.
  • the band-pass filter 110 also includes a group of transconductors 204 that is adapted to receive a voltage V FC - The voltage V FC controls the center frequency of the band-pass filter 200.
  • the band-pass filter 200 includes differential channels 206 and 208, which are coupled to the transconductors 204.
  • the band-pass filter 200 is a 10th order band-pass filter and has a low operating voltage (e.g. 1.6V).
  • V CTR L will move in order to keep the same Fc and BW.
  • a V C TRL of 1.6V corresponds to a center frequency Fc of 4MHz and a bandwidth BW of 3MHz.
  • FIG. 4 is a schematic diagram of a differential channel 400, which can be used to implement each of the differential channels 206 and 208 of Figure 2, in accordance with the present invention.
  • the differential channel 400 includes transconducters 402 to 422 and functions as a passive low-pass filter. The operation of differential channels are well known.
  • Figure 5 is a schematic diagram of a transconductor 500, which may be used to implement each of the transconductors of Figures 2 and 3.
  • the transconductor 500 is referred to as a Nauta transconductor.
  • Nauta transconductors are based on simple inverters and receive a low-impedance control signal. Nauta transconductors and the operation of Nauta transconductors are well known.
  • a DC gain enhancement is realized due to the "negative resistor" principle (INV3, INV4, INV5, and INV6).
  • the transconductor differential (gm_diff) is linear with Vdd.
  • Vdd functions as the control voltage Vc TRL ( Figure 1) for the automatic frequency tuning.
  • FIG. 6 is a schematic diagram of a passive low-pass filter 600, which represents the differential channel 400 of Figure 4.
  • the low-pass filter 600 is a normalized single-ended low-pass 5th order Butterworth filter.
  • the transconductors 402-422 of Figure 4 emulate the resistors and inductors (electronic gyrators) shown in Figure 6.
  • the differential channel 400 is used to implement a low-pass filter, which is in turn used to create the band-pass filter 200 of Figure 2.
  • the differential channel 400 has good sensitivity and dynamic range properties and is thus an ideal component for a gm-C filter.
  • the band-bass filter 200 of Figure 2 In order for the band-bass filter 200 of Figure 2 to be centered on a particular intermediate frequency (IF) and bandwidth (e.g. 4 MHz with a 3MHz bandwidth), the low-pass filter 600 is designed with a particular center frequency (e.g. 1.5 MHz).
  • FIG 7 is a schematic diagram illustrating a complex transformation on internal nodes for the band-pass filter 200 of Figure 2, in accordance with the present invention.
  • the complex transformation is a transformation from the differential channel 400 ( Figure 4) to the band-pass filter 200 ( Figure 2), which is applied using an in-phase signal (I signal) and a quadrature-phase signal (Q signal) (shown as "I” and "Q” in Figure 1).
  • the complex transformation is represented by the following expression: H(Jw) -> H(jw-jwO).
  • the center frequency (Fc) and bandwidth (BW) the band-pass filter 200 can be programmed.
  • two supply voltages are used.
  • One supply voltage V FC is dedicated to controlling the center frequency Fc
  • the other supply voltage VW is dedicated to controlling the bandwidth BW.
  • the center frequency Fc of the band-pass filter 200 is determined by the gm_diff of the set of transconductors 204.
  • the supply voltage V FC of the transconductors in the differential channels 206 and 208 determines the gm_diff of the initial low-pass filter and hence determines the final bandwidth BW of the bass-pass filter.
  • Figure 8 is a chart showing AC responses of the band-pass filter 200 with respect to VFC changes, in accordance with the present invention.
  • Figure 9 is a chart showing AC responses of the band-pass filter 200 with respect to VB W changes, in accordance with the present invention.
  • FIG. 11 is a block diagram showing a complex band-pass filter 1100 where the center frequency Fc and the bandwidth BW are programmable, in accordance with the present invention. Similar to the complex band-pass filter 100 of Figure 1, the complex band-pass filter 1100 includes a band-pass filter 110 and a phase locked loop (PLL) 112, which couples to a reference clock 114 and outputs a control voltage VCTRL- The PLL
  • PLL phase locked loop
  • the complex band-pass filter 1100 also includes a center frequency buffer 1102 and a bandwidth buffer 1104 that provides a voltage ratio such that the supply voltages VF C and V B W are ratios of V CTRL and a bias cell 1105.
  • the bias cell 1105 delivers four bias currents (e.g. ibiasp_CP, ibiasp_VCO, ibiasp_Fc, and ibiasp_BW, which are bias currents for the VCO buffer 126, the center frequency buffer 1102, and the bandwidth buffer 1104, respectively).
  • Three bias voltages e.g. vbiasp, vcasp and vcasn are also used for internal polarization of the buffers 126, 1102, and 1104.
  • the voltage V FC controls/regulates the center frequency Fc
  • the voltage V B W controls or regulates the bandwidth BW. If the process changes as described above in Figure 10, the voltages V FC and V BW track the control voltage V CTRL - The V FC to V BW ratio stays the same.
  • the resistors Rl, R2, R3, and R4 provide resistor ratios and can be adjusted (e.g. by digital commands) to adjust the ratio of the voltages VF C and V B W- Providing programmability to the center frequency Fc and the bandwidth BW offers an alternative for multi-protocol standards with different channels (Fc changes) and for time-acquisition improvements (BW changes).
  • the voltages V FC and VB W have the same properties with regard to the process and temperature variations since the VFC and V B W ratio is a function of the resistor ratio, which is process independent.
  • the voltage V F c (Rl/ Rl + R2)*V C TRL
  • FIG. 12 is a block diagram of an exemplary polyphase filter 1200, in which the band-pass filter 200 of Figure 2 may be implemented, in accordance with the present invention. In this specific embodiment, the bandwidth is programmable.
  • Figure 13 is a simulation schematic of the complex band-pass filter 1300 used to simulate the complex band-pass filter 1100 of Figure 11, in accordance with the present invention.
  • the complex band-pass filter 1300 is similar to the complex band-pass filter
  • the complex band-pass filter 1300 includes optional external capacitors
  • FIG 14 is a block diagram of a voltage controlled oscillator (VCO) 1400, which may be used to implement the VCO 128 of Figures 1 and 11, in accordance with the present invention.
  • the inputs include: supply_ext (external supply [1.8V; 2V]);
  • the outputs include: outputs (outip, outin); and outqp, outqn (LQ differential outputs of the filter).
  • the internal outputs include: sup_Fvco (the output of the PLL_Control bloc and this voltage is then buffered to supply the VCO); VCTRL (the output of the VCO buffer BUF_VCO). This voltage is the initial control voltage of the filter.
  • a multiplication factor obtained thanks to the resistor ratio of the center frequency buffer BUF_Fc and the bandwidth buffer BUF_BW give the both voltages needed to change the initial value of the center frequency Fc and the bandwidth BW.
  • the divider factor of output of the VCO 1400 is 2.
  • Figure 15 is a schematic diagram of a bias cell 1500, which may be used to implement the bias cell 1105 of Figure 11, in accordance with the present invention.
  • Figure 16 is a block diagram of a PLL control cell 1600, which may be used to implement the PDF 120, the charge pump (CP) 122, and the loop filter 124 of Figures 1 and 11, in accordance with the present invention.
  • Figure 17 is a schematic diagram of a PFD 1700, which may be used to implement the PFD 120 of Figures 1, 11, and 16, in accordance with the present invention.
  • Figure 18 is a schematic diagram of a CP 1800, which maybe used to implement the CP 122 of Figures 1, 11, and 16, in accordance with the present invention.
  • Figure 19 is a schematic diagram of a loop filter 1900, which may be used to implement the loop filter 124 of Figures 1, 11, and 16, in accordance with the present invention.
  • FIG 20 is a schematic diagram of a VOC buffer 2000, which may be used to implement the VOC buffer 126 of Figures 1 and 11, in accordance with the present invention.
  • FIG 21 is a schematic diagram of FC and BW buffers 2100, which may be used to implement the FC and BW buffers 1104 and 1106 of Figure 11, in accordance with the present invention.
  • the FC and BW buffers 2100 include a decoder 2102.
  • FIG 22 is a schematic diagram of the decoder 2200, which may be used to implement the decoder 2102 of Figure 21, in accordance with the present invention.
  • the decoder 2200 transforms binary data (e.g., two bits) into four possible "channel" selections.
  • switch commands SW ⁇ i> enter the FC and BW buffers 2100 to program and change the resistor bridge (feedback) in the FC and BW buffers 2100.
  • the present invention provides numerous benefits. For example, it accommodates for process and temperature variations by providing automatic frequency tuning. Embodiments of the present invention also accommodate for process and temperature variations by providing a programmable center frequency and a programmable bandwidth.
  • a complex band-pass filter has been disclosed.
  • the complex band-pass filter includes a band-pass filter that has automatic frequency tuning.
  • the complex band-pass filter also has a programmable center frequency and a programmable bandwidth.
  • the complex band-pass filter also includes a phase locked loop that supplies separate low-impedance control voltages to the band-pass filter. One control programs the center frequency and the other control voltage programs the bandwidth.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)

Abstract

L'invention concerne un filtre passe-bande complexe qui comprend un filtre passe-bande (110) couplé à une source de tension (112). Le filtre passe-bande comprend une première pluralité de transconducteurs (204) recevant une première tension (VFC), laquelle commande la fréquence médiane du filtre passe-bande (110). Ledit filtre passe-bande (110) comprend également une deuxième pluralité de transconducteurs (202) recevant une deuxième tension (VBW), laquelle commande la bande passante du filtre passe-bande. Selon le système de l'invention, le filtre passe-bande complexe présente une fonction de réglage de fréquence automatique contre les variations de processus, une fréquence médiane programmable, et une bande passante programmable. La possibilité de programmer la fréquence médiane (Fc) et la bande passante (BW) offre une alternative pour les normes multiprotocoles avec différents canaux (changements Fc) et pour des améliorations d'acquisition dans le temps (changements BS).
PCT/US2006/041844 2005-11-02 2006-10-25 Filtre passe-bande complexe WO2007053425A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
FR0511160A FR2892872B1 (fr) 2005-11-02 2005-11-02 Filtre passe-bande complexe
FR0511160 2005-11-02
US11/336,121 2006-01-20
US11/336,121 US7248103B2 (en) 2005-11-02 2006-01-20 Complex band-pass filter

Publications (1)

Publication Number Publication Date
WO2007053425A1 true WO2007053425A1 (fr) 2007-05-10

Family

ID=38006191

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2006/041844 WO2007053425A1 (fr) 2005-11-02 2006-10-25 Filtre passe-bande complexe

Country Status (1)

Country Link
WO (1) WO2007053425A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5117205A (en) * 1990-05-01 1992-05-26 U.S. Philips Corporation Electrically controllable oscillator circuit, and electrically controllable filter arrangement comprising said circuits
US6011770A (en) * 1997-12-10 2000-01-04 Texas Instrumental Incorporated Method and apparatus for high-order bandpass filter with linearly adjustable bandwidth
US6137375A (en) * 1999-05-28 2000-10-24 The Trustees Of Columbia University In The City Of New York Loss control loop circuit for controlling the output voltage of a voltage-controlled oscillator
US6930565B1 (en) * 2003-04-28 2005-08-16 Adam S. Vishinsky Fully integrated automatically-tuned RF and IF active bandpass filters
US6968173B2 (en) * 2001-07-19 2005-11-22 Zarlink Semiconductor Limited Tuner

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5117205A (en) * 1990-05-01 1992-05-26 U.S. Philips Corporation Electrically controllable oscillator circuit, and electrically controllable filter arrangement comprising said circuits
US6011770A (en) * 1997-12-10 2000-01-04 Texas Instrumental Incorporated Method and apparatus for high-order bandpass filter with linearly adjustable bandwidth
US6137375A (en) * 1999-05-28 2000-10-24 The Trustees Of Columbia University In The City Of New York Loss control loop circuit for controlling the output voltage of a voltage-controlled oscillator
US6968173B2 (en) * 2001-07-19 2005-11-22 Zarlink Semiconductor Limited Tuner
US6930565B1 (en) * 2003-04-28 2005-08-16 Adam S. Vishinsky Fully integrated automatically-tuned RF and IF active bandpass filters

Similar Documents

Publication Publication Date Title
US6404277B1 (en) Gm-C tuning circuit with filter configuration
US7863972B2 (en) Self-calibration of continuous-time filters and systems comprising such filters
US7463086B2 (en) Apparatus and method for tuning a band pass filter
US6549599B2 (en) Stable phase locked loop having separated pole
CA2014968C (fr) Circuit de filtrage actif
US6462594B1 (en) Digitally programmable phase-lock loop for high-speed data communications
US7403063B2 (en) Apparatus and method for tuning center frequency of a filter
US7248103B2 (en) Complex band-pass filter
US6624668B1 (en) Digitally programmable phase-lock loop for high-speed data communications
JPH05304471A (ja) 走査レシーバ用改良型シンセサイザループフィルタ
US20020145460A1 (en) High speed, low-power CMOS circuit with constant output swing and variable time delay for a voltage controlled oscillator
EP3285397B1 (fr) Circuit de filtre passe-bande actif comportant un dispositif à résistance réglable et un dispositif à capacité réglable
US20080191778A1 (en) Gm/c tuning circuit and filter using the same
KR100906302B1 (ko) 전하 펌프, 이를 포함하는 클록 복구 회로 및 수신기
US20070262813A1 (en) Filter calibration with cell re-use
JP2005328272A (ja) Ｐｌｌ回路およびそれを用いた周波数設定回路
US20090295492A1 (en) Biased varactor networks and methods to use the same
US7012487B2 (en) Transconductance device employing native MOS transistors
US6993106B1 (en) Fast acquisition phase locked loop using a current DAC
JPH1093390A (ja) 相互コンダクタンス増幅器および電圧制御発振器
CN211063586U (zh) 一种跨导电容滤波器及电路
WO2007053425A1 (fr) Filtre passe-bande complexe
Mitić et al. ON DESIGN OF SELF-TUNING ACTIVE FILTERS
Elhallabi et al. High frequency cmos gm-c bandpass filter with automatic on-chip tuning
EP0844739A1 (fr) Boucle à verrouillage de phase, en particulier pour un système émetteur-récepteur

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application
NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 06826776

Country of ref document: EP

Kind code of ref document: A1