Classifications

• • 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
  • H03J1/0091—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor provided with means for scanning over a band of frequencies

Definitions

• the invention relates to an integrated circuit for detecting a received signal, which can be used, for example, in radio receivers and in particular in mobile radio receivers, and to a circuit arrangement with an integrated circuit.
• voltage-controlled oscillators also known as voltage controlled oscillators (VCO)
• VCO voltage controlled oscillators
• PLL phase locked loop
• the voltage-controlled oscillator is tuned in its oscillator frequency with the aid of the phase-locked loop with a certain step size, with frequency-modulated broadcasting in Europe with a frequency step size of 100 kHz.
• the entire FM band (87.5 MHz to 108 MHz) is preferably scanned in 100 KHz steps.
• the frequency of the voltage-controlled oscillator fOsz is typically 10.7 MHz above the input frequency to be received, that is between 98.2 MHz and 118.7 MHz.
• Transmitter found and their input frequency or the corresponding oscillator frequency fOsz of the voltage controlled oscillator are stored. If a transmitter is detected at any reception frequency, the phase control loop is stopped by the microcontroller at the current value. The corresponding values are stored in the microcontroller so that these determined transmitter stations can be set directly at a later point in time. In order to be able to detect the transmitter stations, one or - for increased detection accuracy - several criteria are required to stop the voltage-controlled oscillator at the corresponding oscillator frequency. In the receiver must one or better several evaluation criteria are used to uniquely detect the presence of an input signal worth receiving.
• the multipath signal which indicates whether the received signal is scattered by a multipath reception, can be used in addition to the field strength signal (level of the received signal).
• the field strength signal and the multipath signal are fed to a microprocessor, which digitizes these signals and evaluates them on the basis of criteria specified in the microprocessor.
• the microprocessor decides whether it is a station worth receiving.
• a circuit arrangement of this type has the disadvantage that several lines are required from the receiver module to the microprocessor and unavoidable data traffic takes place on the data bus during the search for a transmitter.
• the data traffic also represents a permanent source of interference in the sensitive reception system.
• the transmitter search criterion of the intermediate frequency counting is therefore often not included, but this does Disadvantage of inaccurate transmitter detection.
• the object is achieved by an integrated circuit for detecting a received signal with the features according to patent claim 1.
• the integrated circuit according to the invention for detecting a received signal has an intermediate frequency detector which, if the intermediate frequency is within a certain range, supplies a first search stop signal. Furthermore, the integrated circuit has a field strength comparator which, if the field strength of the received signal exceeds a field strength setpoint, supplies a second search stop signal. The invention additionally has a multipath comparator on which, if the multipath signal exceeds a certain multipath setpoint, supplies a third search stop signal. Furthermore, a linking device is provided which logically links the three search stop signals to one another to form a binary stop signal which is present statically at the output of the linking device and is available to a microprocessor as its input signal.
• the data traffic between the microprocessor and the integrated circuit is enormously reduced compared to the type of transmitter detection mentioned in the introduction to the description, which results in a strong reduction in interference.
• the integrated circuit according to claim 2 has the advantage that the total area required for the radio receiver can be reduced by the integration of a first analog-digital converter, which is connected upstream of the field strength comparator and is used to digitize the field strength signal.
• a first analog-digital converter which is connected upstream of the field strength comparator and is used to digitize the field strength signal.
• a second analog-digital converter connected upstream of the multipath comparator and used for digitizing the multipath signal has the advantages mentioned in claim 2.
• the integrated circuit according to claim 4 has the advantage that an accelerated signal processing in the field strength comparator is possible by a first serial-parallel converter connected between the first analog-digital converter and the field strength comparator.
• the integrated circuit according to the invention can be adapted to the ambient conditions by setting the field strength setpoint and the multipath setpoint in areas with weak reception to lower values than in areas with strong reception, so that rapid transmitter signal detection is still possible.
• the field strength setpoint, the multipath setpoint and the range within which the intermediate frequency is to be determined are determined by the microprocessor.
• the setpoints can be adapted flexibly, quickly and easily to the ambient conditions without the computing capacity of the microprocessor being appreciably restricted thereby.
• the object directed to a circuit arrangement is achieved by a circuit arrangement comprising an integrated circuit and a microprocessor, in which the integrated circuit has an output connection for the binary stop signal (sstop) which is connected to an input connection of the microprocessor comprising a single line ( ⁇ P) and in which the microprocessor ( ⁇ P) has at least one output connection, which is connected to at least one input connection of the integrated circuit, by means of which the field strength setpoint (la8-14), the multipath signal value (laO-6) and the range (VIN) within which the intermediate frequency (fZF) should lie.
• the integrated circuit has an output connection for the binary stop signal (sstop) which is connected to an input connection of the microprocessor comprising a single line ( ⁇ P) and in which the microprocessor ( ⁇ P) has at least one output connection, which is connected to at least one input connection of the integrated circuit, by means of which the field strength setpoint (la8-14), the multipath signal value (laO-6) and the range (VIN) within which the intermediate frequency (
• the figure shows a block diagram of a possible embodiment of the invention, which contains the essential components for the station search.
• An intermediate frequency counter ZFZ is used to detect whether the intermediate frequency fZF present at the intermediate frequency counter ZFZ, which is the difference between the oscillator frequency fOsz and the reception frequency fE of the received signal, lies within a predetermined range win.
• the win range represents a setpoint which, depending on the desired accuracy, can be specified, for example, by the microprocessor ⁇ P.
• the range win determines the range within which the intermediate frequency fZF may lie in order to be recognized as a transmission signal belonging to a transmitter.
• a first search stop signal cent is present at the output of the intermediate frequency counter ZFZ and can have two different logic states.
• a search stop signal cent with a first logic state indicates that an intermediate frequency fZF has been detected within the range win, whereas the search stop signal cent with the second logic state State indicates that no intermediate frequency fZF was detected within this range win.
• a field strength comparator FsK is provided as a second criterion for the detection of a received signal.
• the field strength comparator FsK compares the field strength signal Fs digitized by a first analog-digital converter AD 1, which was subsequently converted into a 7-bit data word ResO, with a likewise 7-bit field strength setpoint la8-14.
• the conversion of the serial data word into the parallel 7-bit wide data word ResO is carried out by the first serial-to-parallel converter SRI, which has a shift register and a latch.
• a second search stop signal Fsc can be tapped, which, like the first search stop signal cent, can have two logical states.
• the second search stop signal Fsc has a first logic state, this means that the field strength comparator FsK has detected a received signal, whereas if the second search stop signal Fsc assumes the second logic state, no field signal was detected by the field strength comparator FsK.
• a multipath comparator MpK is provided as a third criterion for the detection of the received signal.
• the multipath comparator MpK digitized by the second analog-digital converter ADW2, which is fed to the multipath comparator MpK as a 7-bit data word Resl, with a multipath reference value laO -6 compares.
• the digitized multipath signal Mp is converted by a second serial-to-parallel converter SR2, which is connected between the second analog-digital converter ADW2 and the multipath comparator MpK.
• the third search stop signal Mpc generated by the multipath comparator MpK can also have two logical states, with a received signal being detected by the multipath comparator MpK in the first logical state. In the event that the third scan stop signal Mpc the second assumes a logical state, no receive signal was detected by the multipath comparator MpK.
• the multipath setpoint and the field strength setpoint are read together as a serial data word DIN in a third serial-to-parallel converter SR3 and output as a 14-bit data word la at the output of the third serial-to-parallel converter SR3.
• the first 7 bits of data word la are made available to multipath comparator MpK as multipath setpoint laO-6 and the second 7 bits are provided to field strength comparator FsK as field strength setpoint la8-14.
• the three search stop signals cent, Fsc and Mpc are logically combined with one another by an AND gate AND and give a stop signal sstop at the output of the AND gate AND, which represents the input signal for the microprocessor ⁇ P.
• the stop signal sstop can assume two logical states. In the first logic state, a reception signal was detected in each case by the intermediate frequency counter ZFZ, the field strength comparator FsK and the multipath comparator MpK. If the stop signal sstop assumes the second logic state, then no reception signal was detected by one of the three components intermediate frequency counter ZFZ, field strength comparator FsK or multipath comparator MpK. In this way, the microprocessor ⁇ P is immediately informed whether there is a received signal.
• microprocessor ⁇ P specifies the range win, within which the intermediate frequency must lie, and specifies the setpoints in the form of a serial data word DIN, with which the field strength comparator FsK and the multipath comparator MpK compare the field strength signal Fs and the multipath signal Mp, respectively.
• these three Detectors are weighted individually. As a result, their influence on the search accuracy can be influenced quickly, easily and precisely. In an environment with poor reception characteristics, the target values for the field strength and the multipath signal can be reduced, so that an adaptation to the ambient conditions is possible.
• circuit arrangement according to the invention is not limited to 7-bit data words ResO, Resl, laO-6 and la8-14. Rather, the width of the data words can be selected as required.
• the invention advantageously makes it possible to combine field strength, multipath and intermediate frequency measurement in such a way that it can be indicated by means of a single bit and thus by means of a single pin (housing connection) whether a received signal belonging to a transmitter is present.
• the two analog-digital converters can be implemented by a two-channel 7-bit analog-digital converter, the field strength signal Fs being used as the input signal for the first channel and the multipath signal Mp being used as the input signal for the second channel becomes.
• analog evaluations are usually carried out for the field strength, the multipath signal or the S curve.
• the analog signals are fed to the microprocessor and converted there. The result is that. additional lines with the analog signals must be routed to the microprocessor. If the analog signals are converted before they are fed to the microprocessor, the previously generated digital words are to be transmitted to the microprocessor by bus, which leads to brisk data traffic between the upstream circuit and the microprocessor and the microprocessor additionally with the data transmission and evaluation loaded. This also generates interference signals.
• a known input frequency is counted in the intermediate frequency counter ZFZ within a defined time and evaluated accordingly.
• Window win lies.
• the counting time, the center frequency of the IF frequency to be evaluated and the range win can be set independently of one another. If the measured intermediate frequency fZF lies within the window win, then the corresponding state of the first search stop signal cent is present at the output of the intermediate frequency counter ZFZ. If the measured intermediate frequency fZF lies outside the window win, the first search stop signal cent with the second logic state is present at the output of the intermediate frequency counter ZFZ.
• the intermediate frequency counter ZFZ can be used to indicate whether the frequency fZF to be evaluated is too high or too low.

Landscapes

• Engineering & Computer Science (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
• Noise Elimination (AREA)
• Channel Selection Circuits, Automatic Tuning Circuits (AREA)
• Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
• Circuits Of Receivers In General (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Related Child Applications (1)

Publications (1)

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Family Applications (1)

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Citations (5)

Family Cites Families (5)

• 2000
  • 2000-05-23 DE DE50003128T patent/DE50003128D1/de not_active Expired - Lifetime
  • 2000-05-23 WO PCT/DE2000/001644 patent/WO2001001572A1/de not_active Ceased
  • 2000-05-23 EP EP00945559A patent/EP1188236B1/de not_active Expired - Lifetime
  • 2000-05-23 JP JP2001506136A patent/JP2003503872A/ja not_active Withdrawn
• 2001
  • 2001-12-24 US US10/026,072 patent/US6674813B2/en not_active Expired - Lifetime

Patent Citations (5)

Non-Patent Citations (1)

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