Radio scanner and display system

• US 5,842,119 A
• Filed: 02/05/1993
• Issued: 11/24/1998
• Est. Priority Date: 02/05/1993
• Status: Expired due to Term

• Current Assignee: Xylon LLC (Intellectual Ventures LLC)
• Original Assignee: Geode Electronics L.L.C.
• Inventors: Emerson, Harry Edwin, Freedman, Harry Richard
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): SOBUTKA, PHILIP
• Application Number:
  US08/014,471
• Time in Patent Office: 2,118 Days
• Field of Search: 455/154.2, 455/155.1, 455/158.4, 455/158.5, 455/161.3, 455/161.1, 455/164.1, 455/164.2, 455/169.1, 455/169.2, 455/184.1, 455/186.1 , 455/186.2, 455/182.3, 455/192.3, 455/192.2, 455/195.1, 455/198.1, 455/266.1, 455/226.4, 455/160.1, 455/167.1, 455/132
• US Class Current: 455/161.3
• CPC Class Codes: H03J 1/0066 with means for analysing the received signal strength H03J1/0083 takes precedence
• CPC Class Codes: H03J 1/0083 using two or more tuners
• CPC Class Codes: H04B 1/1027 assessing signal quality or detecting noise/interference for the received signal

Abstract

A method is described for operating a radio receiver in such manner as to accurately and rapidly identify unlistenable, very listenable and marginally listenable channels, and display the listenable and very listenable channels along with an indication of their signal strength, noise and quality on a screen. A reference value of automatic fine tuning voltage is found for the particular receiver. Capacitors that are charged in accordance with the levels of signal strength, noise and automatic fine tuning voltages are sampled before being fully charged at each channel change, and averages of the respective samples are computed as well as the offset between the average of the automatic fine tuning samples and the reference value of automatic fine tuning voltage. A channel having sample averages not meeting certain criteria is rejected as unlistenable, and, of the others, a channel having a very low average on its noise capacitor is identified as very listenable. Those of the remaining channels that are at least marginally listenable are identified by similar analysis of a second group of samples. The criteria for signal strengths and noise may be varied with ambient temperature, and the criteria for noise can be adjusted on the basis of the noisiest channel or the noise produced when the antenna is grounded. Those channels having the greatest signal strength are associated with tuning buttons, and indications of these associations are made on the screen.

Claims

1. A tuning system for a radio receiver comprising:

a visual display of a radio band;

means for tuning the radio receiver so that it tunes to the channels of the band in sequence;

means coupled to said radio receiver for deriving signals indicative of the received signal characteristics of stations present in channels of said radio band, the signal characteristics including at least SS (signal strength), and one of N (noise) and AFT (automatic fine tuning);

means for determining the listenable stations in response to said signals;

means for producing simultaneous displays of said listenable stations at respective channel locations in the visual display, said displays showing at least the relative magnitudes of measured values of the signal strengths of said listenable stations; and

means for tuning the radio receiver to a selected one of the displayed stations for listening.

2. A tuning system as set forth in claim 1, further comprising:

means for modifying said displays so that they illustrate the N of each listenable station.

4. A tuning system as set forth in claim 1, further comprising:

means for deriving digital data broadcast by stations; and

means for presenting said digital data of a tuned in station on the display means.

5. A tuning system as set forth in claim 1 wherein said means for tuning the radio receiver to a selected one of the displayed stations may be effected by touching said display means at the respective displayed location of the selected station.

6. A tuning system as set forth in claim 1, further comprising:

a scanner turner;

said means for deriving said signals being coupled to said scanner tuner; and

means for controlling said scanner turner so that it repetitively scans the channels of the band.

7. A tuning system as set forth in claim 1 further comprising:

means for deriving digital data broadcast by stations wherein said digital data may include the type of program material or other identifying information being broadcast by a station; and

means for simultaneously indicating said identifying information for each of said broadcasting stations on the display means by modifying the appearance of said displays of said signals of listenable stations at respective channel locations in the visual display such as by color, intensity, or shape.

8. A tuning system as set forth in claim 1 further comprising:

means coupled to said radio receiver for deriving digital data broadcast by stations wherein said digital data may include the type of program material or other identifying information being broadcast by a station; and

means for simultaneously presenting an indicator of said identifying information for each of said listenable stations on the display means in an associative manner with said displays.

9. A tuning system as set forth in claim 8 further comprising:

means for selecting which types of said identifying information indicators are to be presented; and

wherein said means for tuning the radio receiver to a selected one of the displayed stations is restricted to tuning to stations associated with said selected types of said identifying information.

10. A tuning system as set forth in claim 9 wherein the identifying information of the selected types is presented and indicators for other listenable stations are not displayed.

3. A tuning system as set forth in 1, wherein:

said means for deriving said signals derives signals for AFT and N;

wherein means are provided for deriving a measure of QF, of the quality of each listenable station in response to a combination of SS, N and AFT; and

wherein means are provided for modifying said displays so that they illustrate the QF of each listenable station.

11. A system for determining whether the signals received by an FM receiver are unlistenable, comprising:

means for deriving a reference value of an automatic fine tuning (AFT) signal of a listenable signal;

means for deriving an AFT signal produced by another station signal;

means for finding the absolute difference between the AFT signal of the listenable signal, and the AFT produced by said another station signal; and

means for identifying the another station signal as being unlistenable if said absolute difference exceeds a predetermined amount.

12. A method for finding a channel having a value of AFT that can be used as a reference value in identifying the listenability of channels in an FM receiver, wherein SS (signal strength), N (noise) and AFT (automatic fine tuning) voltages are produced on respective capacitors, comprising the steps of:

a tuner;

tuning the tuner to a channel in the band;

clamping the voltages across the capacitors to neutral values of voltage;

unclamping the capacitors;

obtaining a first group of samples of the voltage on each capacitor and calculating their respective averages;

rejecting a channel for which the average voltage of the SS samples is less than a given threshold or the average of the N samples is greater than a given limit or the average of the AFT samples lies outside a range of values;

tuning in the next channel and repeating the procedure if the channel is rejected;

obtaining second and third groups of samples of SS, N and AFT;

calculating the voltage averages of each of the second and third group of samples of SS, N and AFT, respectively;

determining the voltage ranges of the samples of SS in each of said second and third groups; and

accepting a channel for the purpose of providing a reference value of AFT, if the voltage averages of said second and third groups of SS samples are both greater than a predetermined threshold value, the voltage ranges of SS values of the samples in said second and third groups are within a given percentage of each other, the voltage averages of the samples of N for both groups are less than a given limit and the difference between the voltage averages of the AFT samples of both groups is less than a given voltage, which is less than said given value with which the first group of AFT samples is compared.

13. A method for finding a channel having a value of AFT that can be used as a reference value as set forth in claim 12 but wherein the second and third groups of samples are obtained from the strongest station by the addition of the following steps prior to obtaining the second and third groups of samples:

recording a channel in memory along with the average voltage of its SS samples if it is not rejected;

checking to see if all channels of the band have been subjected to the procedure;

tuning to the channel having a station with the greatest average voltage of the SS samples; and

,

tuning to the channel with the next greatest average voltage of the SS samples and repeating the procedure if the channel is not accepted.

14. A method for identifying a channel having a listenable station in an FM receiver having capacitors that are charged by voltages in its tuner for SS (signal strength), N (noise) and AFT (automatic fine tuning) there being respective time constants for the charging of each capacitor, comprising the steps of:

providing a reference value of AFT;

momentarily clamping said capacitors for SS, N and AFT to respective neutral voltage values at a change in channel;

obtaining the value of a first group of individual samples or the average of a first group of multiple samples of the voltage of each of said capacitors so as to obtain an SS average, an N average, and an AFT average;

computing the offset between the reference value of AFT and the AFT value or average; and

rejecting a channel as not having a listenable station if the SS value or average is less than a given threshold, the N value or average is greater than a first limit, or its AFT offset exceeds a given range, the remaining channels being accepted as listenable.

15. A method for identifying a channel having a listenable station in an FM receiver having capacitors that are charged by voltages in its tuner for SS (signal strength), N (noise) and AFT (automatic fine tuning) there being respective time constants for the charging of each capacitor, comprising the steps of:

providing a reference value of AFT;

momentarily clamping said capacitors for SS, N and AFT to respective neutral voltage values at a change in channel;

obtaining the value of a first group of individual samples or the average of a first group of multiple samples of the voltage of each of said capacitors so as to obtain an SS average, an N average, and an AFT average;

computing the offset between the reference value of AFT and the AFT value or average; and

rejecting a channel as not having a listenable station if the SS value or average is less than a given threshold, the N value or average is greater than a first limit, or its AFT offset exceeds a given range, the remaining channels being accepted as potentially listenable.

16. A method as set forth in claim 15, wherein an accepted channel is identified as very listenable if its N value or average is below a second limit that is less than said first limit so as to indicate that it has virtually no noise, the remaining channels being accepted as potentially listenable.

17. A method as set forth in claim 15, wherein a channel that has been accepted as potentially listenable is accepted as listenable by:

obtaining the average of a second group of samples of the voltage of each of said capacitors so as to obtain a second SS average, a second N average, and a second AFT average;

computing the AFT offset between the reference value of AFT and the second AFT average; and

identifying said channel as having a listenable station if the second SS average is greater than a threshold value, the second N average is less than a third limit, and the AFT offset less than a given voltage, the remaining channels being rejected.

18. A method as set forth in claim 15, wherein a channel that has been accepted as potentially listenable is accepted as listenable by:

obtaining the average of a second group of samples of the voltage of each of said capacitors so as to obtain a second SS average, a second N average, and a second AFT average;

computing the AFT offset between the reference value of AFT and the second AFT average;

obtaining the quality factor, QF, for a given channel that was rejected in said accepting step; and

accepting said channel if it has a quality factor greater than a predetermined value, the remaining channels being rejected.

19. A method as set forth in claim 15 wherein a channel identified as unlistenable therein is re-examined by:

determining if its identification as unlistenable was only due to noise;

taking another sample of the voltage on the N capacitor if this is the case; and

identifying the channel as being listenable if the voltage of this last sample is not greater than it would be at the time of said another sample if the signal for N were at its maximum value.

20. A method as set forth in claim 15, further comprising the steps of:

recording accepted channels on a tuning list;

repeating the procedure beginning with the step of momentarily clamping the capacitors to neutral voltages until all channels of the band have been subjected to the procedure; and

respectively associating the channels having the largest average values of SS with memory buttons if a best station memory scanning button has been activated.

21. A method for rapidly identifying channels of an FM band having listenable stations on a receiver providing SS (signal strength), N (noise), and AFT (automatic fine tuning) voltages on respective capacitors, comprising the steps of:

providing a reference voltage of AFT;

momentarily clamping the capacitors to neutral voltages;

applying for a given channel associated SS, N, and AFT signals to said capacitors, respectively;

obtaining the averages of a first group of one or more samples of each of the SS, N and AFT voltages;

computing the offset between the average of the AFT samples from the reference value of AFT;

rejecting on the basis of the averages of SS and N and the AFT offset not meeting first criteria those channels not having a station that is even marginally listenable;

repeating the procedure beginning with the sampling until all channels of the band have been analyzed;

identifying the non-rejected channels as being very listenable if they have virtually no noise;

obtaining the averages of a second group of samples of each of the SS, N and AFT voltages for the channels that have not been rejected or identified as being very listenable;

computing the AFT offset of the average of the second samples with respect to the AFT reference voltage; and

identifying as having at least marginally listenable stations those channels having SS and N averages and an AFT offset that meet second criteria.

22. A method of operation of a receiver having a listening tuner and a scanning tuner comprising:

repeatedly tuning said scanning tuner across a band of channels;

providing first indications as to which channels received by said scanning tuner are listenable and second indications as to listenable channels that contain data different from the audio signal;

forming a simultaneous display in response to said first indications of all listenable channels in a band showing the relative magnitude of measured values of their signal strengths;

forming a simultaneous display in response to said second indications illustrating the content thereof;

tuning said listening tuner to a desired channel; and

forming a display for this channel of data received therein in addition to the audio information.

23. In a tuning system where channels are identified as being listenable or unlistenable on the basis of the difference between their AFT voltage and a reference AFT voltage, a method for finding a reference AFT voltage comprising:

tuning the system across a band of channels;

finding the strongest channel; and

using the AFT voltage of the strongest channel as the reference AFT voltage.

24. In a tuning system where channels are identified as being listenable or unlistenable on the basis of the difference between their AFT voltage and a reference AFT voltage, a method for finding a reference AFT voltage comprising:

tuning the system across a band of channels;

finding a very listenable channel; and

using the AFT voltage of said very listenable channel as the reference AFT voltage.

25. In a tuning system for a radio, a method of determining a Quality Factor QF of a channel comprising:

a means of obtaining samples of N and AFT;

taking the averages of said samples;

a means of obtaining a reference value of AFT;

subtracting the AFT average from the reference value to obtain an AFT offset;

and,

computing a QF as a factor of N, and AFT offset that is representative of the listenability of the received signal.

26. In the method for a tuning system as set forth in claim 25, wherein said step of QF computation is computed as follows:

take the square foot of N average times AFT offset, then add N range divided by two.

27. In a tuning system as set forth in claim 25, said method further including the steps of:

obtaining samples of signal strength (SS);

taking the average of said SS samples; and

including the average of said SS as a factor in the step of computing QF.

28. A method for identifying the listenability of channels in an FM receiver including a city/highway driving switch, a display, and a tuner, wherein SS (signal strength), N (noise) and AFT (automatic fine tuning) voltages are produced on respective capacitors, comprising the steps of:

determining whether said switch is in the city or in the highway position;

setting respective signal strength thresholds at higher values when said switch is in the highway position than when it is in the city position;

tuning the tuner to a channel in the band;

clamping the voltages across the capacitors to neutral values of voltage;

unclamping the capacitors;

obtaining a first group of samples of the voltage on each capacitor and calculating their respective averages;

rejecting a channel for the purpose of providing a reference value of AFT if the voltage average of SS samples are below a predetermined threshold value, or if the voltage average of N samples are greater than a given limit, or if the AFT voltage average is less than a given value;

tuning in the next channel and repeating the procedure if the channel is rejected;

obtaining second and third groups of samples of SS, N, and AFT;

accepting a channel for the purpose of providing a reference value of AFT, if the voltage averages of said second and third groups of SS samples are both greater than a predetermined threshold value, the voltage ranges of SS values of the samples in said second and third groups are within a given percentage of each other, the voltage averages of the samples of N for both groups are less than a given limit and the difference between the voltage averages of the AFT samples of both groups is less than a given voltage, which is less than said given value with which the first group of AFT samples is compared;

accepting the average of the combined averages of the second and third groups of AFT voltages as the AFT reference value;

tuning in the next channel and repeating the procedure of obtaining a first group of samples of SS, N, and AFT and calculating their voltage averages;

rejecting a channel as definitely not listenable, for which the average voltage of the SS samples is less than a given threshold, or the average of the N samples is greater than a given limit, or the average of the AFT samples are offset from the reference value of AFT by more than a predetermined amount;

tuning in the next channel and repeating the procedure if the channel is rejected;

obtaining second and third groups of samples of SS, N and AFT;

calculating the voltage averages of each of the second and third group of samples of SS, N and AFT, respectively;

determining the voltage ranges of the samples of SS in each of said second and third groups; and

analyzing the remaining channels to identify those that are very listenable;

analyzing the remaining channels to see if they are at least marginally listenable; and

forming a display at respective locations of the average signal strength of the listenable channels.

29. In a tuning system for a receiver in which channels of a band are identified as listenable or unlistenable by comparing the strength of the received signal with a threshold value and wherein a city/highway driving switch is provided, said tuning system comprising:

means for determining whether said switch is in the city or in the highway position;

means for setting signal strength thresholds at higher values when said switch is in the highway position than when it is in the city position;

means for momentarily charging a capacitor to a neutral value when the system operates to tune from a first channel to a second channel;

means for applying a voltage to said capacitor corresponding to a characteristic of signals received in a channel;

an integration or filter circuit including said capacitor coupled to said voltage;

means for obtaining samples of the voltage across the capacitor at such times that the effect of artifacts on the average value of said samples is reduced;

means for deriving said average value;

means for identifying if a channel is listenable by determining if a characteristic is acceptable by comparing the value of the sample or the average of multiple samples with the voltage that would be across the capacitor at the time of the samples if a voltage corresponding to a limit for the characteristic were applied to the integration or filter circuit;

means responsive to said signals for producing displays at respective locations of identified listenable stations in the band; and

means for tuning the radio receiver to a selected one of the displayed stations.

30. A tuning system for a radio receiver comprising:

a visual display of a radio band;

means for tuning the radio receiver so that it tunes in the channels of the band;

means for deriving signals indicative of the received signal characteristics of stations present in channels of said radio band, the signal characteristics including at least SS (signal strength), and one of N (noise) and AFT (automatic fine tuning);

means for determining the listenable stations in response to said signals;

means for producing simultaneous display of said listenable stations at respective channel locations in the visual display, with the signals being displayed showing at least the relative magnitudes of measured values of the signal strengths of said listenable stations;

means for deriving digital data broadcast by stations wherein said digital data may include the type of program material or other identifying information being broadcast on a station;

means for simultaneously indicating said identifying information for each of said listenable stations on the display means by modifying the appearance of said displays of said listenable stations at respective channel locations in the visual display such as by color, intensity, or shape; and

means for tuning the radio receiver to a selected one of the displayed stations for listening.

31. A tuning system as set forth in claim 30 further comprising:

means for selecting which types of said identifying information are to modify said displays; and

wherein said means for tuning the radio receiver to a selected one of the displayed stations for listening is restricted to tuning to stations associated with said selected types of said identifying information.

32. A tuning system as set forth in claim 30 wherein said means for simultaneously indicating said identifying information for each of said broadcasting stations on the display means may be accomplished by presenting an indicator of said identifying information for each of said broadcasting stations on the display means in an associative manner with said displays of said signals of listenable stations at respective channel locations in the visual display.

33. A tuning system for a radio receiver having a listening tuner comprising:

a visual display of a radio band;

means including a scanner tuner for tuning in the channels of a band in sequence;

means for controlling said scanner tuner so that it repetitively scans the channels of the band;

means for deriving signals indicative of the reception characteristics of stations tuned in by said scanner tuner, the reception characteristics including at least SS (signal strength, and one of N (noise) and AFT (automatic fine tuning);

means for determining the listenable stations in response to said signals;

means for producing simultaneous displays of said signals of listenable stations at respective channel locations in the visual display, with the signals being displayed for showing at least the relative magnitudes of measured values of the signal strengths of said listenable stations;

means for deriving digital data broadcast by stations wherein said digital data may include the type of program material or other identifying information being broadcast on a station;

means for simultaneously indicating said identifying information for each of said listenable stations on the display means by modifying the appearance of said displays such as by color, intensity, or shape; and

means including a listening turner for tuning the radio receiver to a selected one of the displayed stations for listening.

34. A tuning system as set forth in claim 33 further comprising:

a means for selecting which types of said identifying information indications may be presented; and

wherein said means for tuning said listening tuner to a selected one of the displayed stations for listening is restricted to tuning to stations associated with said selected types of said identifying information.

35. A tuning system as set forth in claim 33 wherein said means for simultaneously indicating said identifying information for each of said broadcasting stations on the display means may be accomplished by presenting an indicator of said identifying information for each of said broadcasting channels on the display means in an associative manner with said displays of said signals of listenable stations at respective channel locations in the visual display.

36. A tuning system including:

means for controlling the tuning system to tune through the channels of a band;

means for deriving received signal characteristics for each channel tuned to, said characteristics including an AFT (automatic fine tuning) measurement of frequency deviation of a channel;

means for providing a voltage representing the amplitude of AFT for each channel tuned to, wherein said voltage varies above and below a center voltage, said center voltage representing zero frequency deviation;

an integration filter circuit, said circuit including a capacitor coupled to receive said AFT voltage; and

means including a switch for momentarily causing the voltage on said capacitor to have a value corresponding to said AFT center voltage as the system operates to tune from a first channel to a second channel.

37. A radio including:

means for applying a voltage to a capacitor corresponding to an AFT (automatic fine tuning) characteristic of signals received in a channel, said AFT representing frequency deviation of said channel, and said AFT voltage further incorporating unwanted artifacts from recovered audio signals which vary in voltage above and below a center voltage caused by said AFT;

means for obtaining samples of the voltage across the capacitor at such times that the average value of said samples substantially cancels the effect of the audio artifacts on the AFT voltage capacitor and substantially equals the actual center voltage caused by said AFT; and

means for deriving said average value.

38. A method for identifying channels of a band as being unlistenable, very listenable or listenable in a radio scanner including computerized means and means for producing electrical signals respectively indicative of different aspects of the quality of reception that change in value after each channel is tuned in comprising the steps of:

tuning in the receiver to the channels of a band;

identifying a channel as being unlistenable if the electrical signals obtain respective values of a first criteria during a first period following the tuning in of a channel or as being very listenable if the electrical signals obtain values of a second criteria during said first period; and

determining whether the channels that have not been identified as being unlistenable or as being very listenable are listenable depending on whether or not the electrical signals have obtained values of a third criteria during a second period after the tuning in of a channel that is longer than the first period.

39. A method as set forth in claim 38, wherein the first and second periods for each channel are consecutive after the tuning of a channel.

40. A method as set forth in claim 38 wherein:

the first period for each channel follows the tuning in of each channel during a first pass through the band; and

the second period for each channel follows the tuning in of each channel during a second pass through the band.

41. A tuning system including:

means for controlling the tuning system to tune through the channels of a band;

means for deriving received signal characteristics for each channel tuned to;

means for providing a voltage representing the amplitude of each received signal characteristic for each channel tuned to;

an integration filter circuit for each of said received signal characteristics, said circuit including a capacitor coupled to receive each said voltage, respectively; and

means including a switch for momentarily clamping each said capacitor causing the voltage on each said capacitor to have a value corresponding to the value it has when the amplitude of the associated characteristic is zero as the system operates to tune from a first channel to a second channel.

42. A tuning system as set forth in claim 41, further comprising:

means for deriving one or more samples of the voltage on said capacitor after said momentary charging and before said capacitor becomes fully charged; and

means for determining if a characteristic is acceptable by comparing the value of one of the sample and the average of multiple samples with the voltage that would be across the capacitor at the time of the samples if a voltage corresponding to a limit for the characteristic were applied to the integration or filter circuit.

43. In a radio receiver that supplies at least one of signal strength (SS), noise (N), and automatic fine tuner (AFT) signals to associated capacitors, respectively, for integration or filtering of said signals, said capacitors being connected in a circuit with respective resistors so as to have predetermined respective charging time constants, apparatus for deriving the final integrated or filtered values comprising:

means for indicating the times at which the charging of said capacitors begins;

means for obtaining sample voltages across the respective capacitors at given times after the time when charging begins and before the capacitors are fully charged; and

means for processing the sample voltages so as to obtain via extrapolation indications of the voltages that would appear on the capacitors when they are fully charged.