Radio scanner and display system

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.