EP2774270A1 - Temperature compensated frequency adjustment in a meter reading endpoint - Google Patents
Temperature compensated frequency adjustment in a meter reading endpointInfo
- Publication number
- EP2774270A1 EP2774270A1 EP12846716.4A EP12846716A EP2774270A1 EP 2774270 A1 EP2774270 A1 EP 2774270A1 EP 12846716 A EP12846716 A EP 12846716A EP 2774270 A1 EP2774270 A1 EP 2774270A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- temperature
- crystal
- pll
- frequency
- endpoint
- 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.)
- Withdrawn
Links
- 239000013078 crystal Substances 0.000 claims abstract description 64
- 238000000034 method Methods 0.000 claims abstract description 28
- 238000012544 monitoring process Methods 0.000 claims description 12
- 230000008859 change Effects 0.000 claims description 7
- 230000008878 coupling Effects 0.000 claims description 4
- 238000010168 coupling process Methods 0.000 claims description 4
- 238000005859 coupling reaction Methods 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- 230000005611 electricity Effects 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 abstract description 3
- 238000010586 diagram Methods 0.000 description 4
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 239000010453 quartz Substances 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
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- 238000012360 testing method Methods 0.000 description 2
- 238000007792 addition Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000013480 data collection Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 238000012552 review Methods 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 238000006467 substitution reaction 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
- H03L1/00—Stabilisation of generator output against variations of physical values, e.g. power supply
- H03L1/02—Stabilisation of generator output against variations of physical values, e.g. power supply against variations of temperature only
- H03L1/022—Stabilisation of generator output against variations of physical values, e.g. power supply against variations of temperature only by indirect stabilisation, i.e. by generating an electrical correction signal which is a function of the temperature
- H03L1/027—Stabilisation of generator output against variations of physical values, e.g. power supply against variations of temperature only by indirect stabilisation, i.e. by generating an electrical correction signal which is a function of the temperature by using frequency conversion means which is variable with temperature, e.g. mixer, frequency divider, pulse add/substract logic circuit
-
- 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
- H03L7/16—Indirect frequency synthesis, i.e. generating a desired one of a number of predetermined frequencies using a frequency- or phase-locked loop
- H03L7/18—Indirect frequency synthesis, i.e. generating a desired one of a number of predetermined frequencies using a frequency- or phase-locked loop using a frequency divider or counter in the loop
Definitions
- TITLE TEMPERATURE COMPENSATED FREQUENCY ADJUSTMENT IN A METER READING ENDPOINT
- the presently disclosed subject matter relates to stabilization of operating frequencies in metrology endpoints. More specifically, the presently disclosed subject matter relates to methods and apparatus for providing
- AMR Automatic Meter Reading
- consumption measuring devices such as, but not limited to, water, gas, and oil meters.
- Such endpoints are generally constructed as very low cost devices due, in part, to the need to provide large numbers of such devices to provide utility consumption data from large numbers of consumers. Due to the financial need to maintain manufacturing costs for such devices low, such devices may not be able to be manufactured to provide tight tolerances for many operational aspects thereof without incurring adverse impacts on such manufacturing costs.
- ISM industrial, scientific, and medical
- the receive bandwidth must be kept wider than necessary to make sure the endpoint is heard. It is desirable to limit the drift to a relatively much lower amount, such as an amount less than about 4 PPM. It is important, however, to limit drift in any narrowband system regardless of operating frequency.
- TXCO temperature compensated crystal oscillator
- a designer may employ components, typically capacitors, to "pull" the frequency of the crystal as the temperature changes. Crystals typically can be pulled by a small amount, that is, crystal's resonant frequency may be shifted slightly using known techniques. To minimize the amount of pull needed, crystals cut with angles producing flat curves are desired. These would be cuts from +4' or +5' angles. Crystal manufacturers can hold a cut angle typically to ⁇ 1 ' of cut. The problem with this is the difference in tolerance between curves +4', +5', and +6' can be as high as 5 PPM at the temperature extremes (-40°C. to +85°C). Variations of such amount require the TCXO designer to test each crystal to know how much compensation is needed. This adds cost to the TCXO.
- the presently disclosed subject matter relates to a method for providing temperature compensated operation of an endpoint incorporating a phase locked loop (PLL) for producing an output frequency.
- the method monitors temperature associated with a reference frequency producing component associated with the PLL and then adjusts operation of the PLL to compensate for temperature induced changes in the operating frequency of the reference frequency producing component whereby a predetermined output frequency of the PLL is maintained.
- PLL phase locked loop
- the method comprises monitoring the temperature of a crystal controlled oscillator. In alternative embodiments, the method comprises monitoring the temperature of a controller associated with the endpoint. In certain embodiments, the crystal has a high temperature versus frequency change curve and in selected such embodiments the crystal has a cut angle of from about -5' to 0'.
- the method provides adjustment by modifying an operational characteristic of at least one component of the PLL.
- characteristic of a feedback loop of the PLL may be modified.
- the presently disclosed subject matter also relates to a temperature compensated endpoint.
- Such endpoint comprises a controller, a radio frequency (RF) transmitter, a phase locked loop (PLL) circuit configured to establish the transmitter operating frequency, a crystal controlled oscillator configured to couple a reference signal to said PLL and at least one temperature sensor, in such endpoints, the controller is configured to receive temperature related signals from the temperature sensor and to modify operation of said PLL based on the temperature related signals to maintain a predetermined transmitter frequency.
- a memory is associated with the controller.
- the temperature related signals are related to the temperature of the crystal in the crystal controlled oscillator and the memory is configured to store information relating crystal temperature to changes in operating frequency.
- At least one temperature sensor is positioned proximate the crystal controlled oscillator while in other embodiments, the at least one temperature sensor is positioned proximate the controller.
- the endpoint includes a metrology device configured to measure utility consumption.
- the controller is configured to receive utility consumption data from the metrology device and causes the RF transmitter to transmit signals relating to the consumption data.
- the metrology device is configured to measure one of water, gas, oil, and electricity consumption,
- a battery operated power supply is provided and configured to supply operating power to the controller, the radio frequency (RF) transmitter, and the phase locked loop (PLL) circuit.
- RF radio frequency
- PLL phase locked loop
- the presently disclosed subject matter also relates to methodologies for maintaining a stable output frequency from a phase locked loop (PLL) circuit.
- the method calls for coupling a crystal controlled oscillator as a reference input to a PLL circuit, monitoring a temperature associated with the crystal controlled oscillator, ascertaining expected deviations in the crystal's operating frequency based on the monitored temperature, and modifying operational characteristics of the PLL to maintain a stable output from the PLL based on the expected deviations.
- the methodology calls for monitoring the temperature of the crystal.
- expected deviations in the crystal's operating frequency may be ascertained by examination of a look up table.
- Figure 1 is a graphical representation corresponding to different temperature response curves for crystal controlled oscillators whose crystals are cut at different angles;
- Figure 2 is a block diagram of an endpoint device incorporating temperature compensation features in accordance with the presently disclosed subject matter.
- Figure 3 illustrates a block diagram of an exemplary phase locked loop that may be employed with the presently disclosed subject matter.
- the presently disclosed subject matter is particularly concerned with providing a temperature compensation arrangement using low-cost crystals while maintaining the frequency stability of the associated transmitter circuitry.
- FIG. 1 With initial reference to Figure 1 , there is illustrated a graphical representation 100 corresponding to different exemplary temperature response curves for crystal controlled oscillators whose crystals are cut at different angles.
- graphs similar to graph 00 are generally known and demonstrate the known temperature characteristics of cut quartz crystals as related to the crystal cut angle.
- representative characteristic lines are illustrated indicating crystal cuts ranging from -5' to + 5' over a temperature range of about -70°C to about 120°C.
- Graph 100 also illustrates, by way of vertical scale, a range in parts per million (PPM) expected variations in operating frequency ranging from about -70 to +80 PPM.
- PPM parts per million
- FIG. 2 there is illustrated a block diagram 200 of an endpoint device 210 incorporating temperature compensation features in accordance with the presently disclosed subject matter.
- the presently disclosed subject matter is exemplarily described as being in association with an endpoint device, such is not a specific limitation of the presently disclosed subject matter. More specifically, it should be apparent to those of ordinary skill in the art upon reading of the present disclosure that the presently disclosed subject matter may easily and benifically be applied in any situation where temperature compensation of any device including a PLL is desirable.
- endpoint device 210 corresponds, at least in part, to a crystal controlled oscillator 212 that may correspond to a reference oscillator for use in association with a phase locked loop (PLL) 222 portion of an RF transmitter 216.
- Endpoint device 210 also includes controller 214 which may correspond to a microprocessor, application specific integrated circuit (ASIC), or other device capable of providing necessary controling features such as for endpoint operation.
- ASIC application specific integrated circuit
- Controller 214 may also include on board memory 234 for storing operational software as well as collected data from associated metrology devices when involved (not separately illustrated) and other data related to endpoint or metrology device operation.
- memory 234 may also correspond to (represent) in whole or in part memory devices external to controller 214. All components of endpoint 210 requiring operational power including, for example, controller 214 and RF transmitter 216, may be configured to receive such operating power from battery power supply 218.
- PLL 222 is provided to maintain a stable operating frequency for RF transmitter 216.
- a phase locked loop (PLL) 300 is a control system that generates an output signal V 0 UT whose phase is related to the phase of an input or reference signal VIN.
- reference signal is provided by oscillator 212.
- PLL circuits include a variable frequency output oscillator 302, exemplarily a voltage controlled oscillator (VCO), and a phase detector 304.
- VCO voltage controlled oscillator
- phase of the reference signal VIN is compared with the phase of the output signal VOUT SO as to adjust the frequency of oscillator 302 to keep the phases matched.
- the signal from the phase detector 304 may be passed through a loop filter 306 to control the oscillator 302 in a feedback loop.
- a divider 308 may be included in the feedback loop to permit the oscillator 302 to operate at a higher frequency than the reference signal.
- the output signal VOUT from oscillator 302 may be multiplied in additional circuitry (not separately illustrated) to produce a higher frequency output signal.
- a representative temperature sensor 220 may be associated with crystal controlled oscillator 212 and configured to forward temperature related signals via line 232 to controller 214.
- a temperature sensor 230 (represented in dotted lines) associated with controller 214 may be employed to provide temperature related signals to processor 214.
- controller 214 in endpoint 210 to measure the temperature and to reprogram the operating frequency in the phase locked loop (PLL) 222.
- the operating frequency of RF transmitter 216 that converts the crystal frequency produced by oscillator 2 2 to a desired frequency may be temperature
- any of the components of PLL 300 may be effective to adjust the output frequency of oscillator 302.
- T us, for example, in the instance that a divider 308 is provided, changes in the divider ratio may be programmed by controller 214 to effect a change in the output frequency of oscillator 302.
- an offsetting bias voltage may be applied to a voltge control input of oscillator 302 in the instance that such oscillator is configured as a voltage controlled oscillator (VCO).
- VCO voltage controlled oscillator
- the desired output frequency may correspond to a frequency in the 915 MHz ISM band, other ISM bands and other frequecies may be selected as desired or required.
- Such alternative frequency bands include, but are not limited to, 433 MHz, and 931 MHz.
- the radio frequency integrated circuit (RFIC) used in many endpoints includes a built in temperature sensor, for example, representative sensor 250 (shown in dotted line).
- sensor 250 may be used to supply data points for use with a look up table to alter the PLL frequency.
- the temperature signal may be considered at least reiated to that of the crystal controlled oscillator based, at least in part, on proximity of the sensor due to their proximity within endpoint 210.
- endpoint devices constructed in accordance with the presently disclosed subject matter may include metrology components such as metrology component 240 illustrated in Figure 2.
- Metrology component 240 may correspond to any number of devices whose purpose is to measure consumption of, for example, a utility or a commodity. Such utilities and commodities may include, but are not limited to, water, gas, oil, and electricity.
- data generated by metrology device 240 would be received and processed by controller 214 for storage and/or transmission via RF transmitter 216 to a remote location.
- a remote location may correspond to a central facility (not separately illustrated) for example, for the utility where data collection, billing, and other functionalities may be conducted.
- a crystal cut at -4' produces a high, that is, very steep temperature vs. PPM (frequency) change curve, Such curves can easily be compensated for in the controller 214 or RFIC using the presently disclosed subject matter. Since manufacturers can maintain cuts within ⁇ 1 ', a crystal cut at -4' might be as low as -5' or as high as -3'. The difference between such cuts is only around ⁇ 2 PPM, Such small error is tolerable and doesn't require testing of each crystal.
Landscapes
- Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/289,237 US8968096B2 (en) | 2010-02-12 | 2011-11-04 | Game server and player control program |
CA2758362A CA2758362C (en) | 2011-11-04 | 2011-11-14 | Temperature compensated frequency adjustment in a meter reading endpoint |
PCT/US2012/062688 WO2013066939A1 (en) | 2011-11-04 | 2012-10-31 | Temperature compensated frequency adjustment in a meter reading endpoint |
Publications (2)
Publication Number | Publication Date |
---|---|
EP2774270A1 true EP2774270A1 (en) | 2014-09-10 |
EP2774270A4 EP2774270A4 (en) | 2015-07-01 |
Family
ID=48195137
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP12846716.4A Withdrawn EP2774270A4 (en) | 2011-11-04 | 2012-10-31 | Temperature compensated frequency adjustment in a meter reading endpoint |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP2774270A4 (en) |
WO (1) | WO2013066939A1 (en) |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
ATE77185T1 (en) * | 1987-09-28 | 1992-06-15 | Siemens Ag | METHOD OF TEMPERATURE COMPENSATION OF A VOLTAGE CONTROLLED CRYSTAL OSCILLATOR IN A PHASE LOCKED LOOP. |
US5856766A (en) * | 1997-06-30 | 1999-01-05 | Motorola Inc. | Communication device with a frequency compensating synthesizer and method of providing same |
JP3160299B2 (en) * | 1997-07-11 | 2001-04-25 | 松下電器産業株式会社 | Function generation circuit, crystal oscillation device, and method of adjusting crystal oscillation device |
JP2000201072A (en) * | 1999-01-06 | 2000-07-18 | Nec Corp | Pll circuit using temperature compensating vco |
BR0112613A (en) * | 2000-07-21 | 2003-07-29 | Itron Inc | Scattered Spectrum Meter Reading System, Meter Endpoint Encoder Transmitter, and Utility Meter Reading System |
US7215214B1 (en) * | 2003-09-26 | 2007-05-08 | Cypress Semiconductor Corp. | Resonator and amplifying oscillator circuit having a high resolution skew-compensated frequency synthesizer integrated on a single substrate |
US20050238044A1 (en) * | 2004-04-26 | 2005-10-27 | Osterloh Christopher L | System and method for utility data collection |
DE602004030953D1 (en) * | 2004-06-24 | 2011-02-17 | Nokia Siemens Networks Oy | FREQUENCY SYNTHESIZER |
US7449968B1 (en) * | 2005-05-03 | 2008-11-11 | Discera, Inc. | Frequency and temperature compensation synthesis for a MEMS resonator |
US7579919B1 (en) * | 2007-10-13 | 2009-08-25 | Weixun Cao | Method and apparatus for compensating temperature changes in an oscillator-based frequency synthesizer |
-
2012
- 2012-10-31 WO PCT/US2012/062688 patent/WO2013066939A1/en active Application Filing
- 2012-10-31 EP EP12846716.4A patent/EP2774270A4/en not_active Withdrawn
Also Published As
Publication number | Publication date |
---|---|
WO2013066939A1 (en) | 2013-05-10 |
EP2774270A4 (en) | 2015-07-01 |
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