FI98022C - Method and apparatus for conducting a listener survey of radio stations - Google Patents

Description

98022

Method and apparatus for conducting a listener survey of radio stations

The invention relates to a method for conducting a lunar survey of radio stations.

The invention also relates to an apparatus for conducting a listener survey of radio stations, which apparatus comprises a radio receiver unit and an antenna means connected thereto.

The present invention relates to the performance of listener surveys of public radio stations, in particular commercial radio stations and broadcasting stations. Conducting listener surveys is a way for radio stations to find out the popularity of a radio station. Listener surveys are a way of measuring the popularity of a radio station, the results of which allow radio stations to develop their competitiveness. The most important factor in reaching the number of listeners for radio stations is to develop the program to be broadcast in such a way that it achieves the greatest possible popularity among listeners.

20 This is particularly important for commercial radio stations whose activities are based on the sale of advertising time covered by a program intended for listeners.

The listener surveys are carried out both by the radio stations themselves and by companies specializing in the listener surveys. Traditionally, surveys of radio stations have been • • * ··· * conducted through interviews. However, such »· · ... t methods are very laborious to perform, • · · ·. · · Require the use of human resources, are costly and, in addition, have unreliable results,: 30 because the interview situation is rarely real-time itself • · ·: * · *: with listening to a radio station. For the reasons mentioned above, listener surveys are relatively infrequent. For the reasons set out above, the use of the results of the interview methods for the development of the radio station's program is a kind of search shoot, as it is difficult to obtain direct private information on the effects of various factors on listener popularity from these results.

Technical tools and methods have also been developed to determine the number of listeners. One such method is one in which a statistically large group of subjects, for example, 2,000 subjects, is provided with a listening device that registers the signal signals hidden in the transmission signal of the radio stations. The signals of different radio stations are, of course, different in order to allow a study of 10 listeners. The results recorded by the listening devices are later decoded into a common data processing device, which calculates the numbers and proportions of listeners at the different stations. In this way, better and more reliable results are obtained than with interview methods. However, the method is in a way artificial because it provides a special listening device for pre-determined subjects. The artificiality is enhanced by the fact that the person using the listening device knows that his change of listening position to another is noticed, and this can affect how sensitively a person eventually changes the listened radio station to another. The method requires a large number, such as 2,000 active subjects and an equal number of listening devices, as well as "changes to the equipment of the radio stations in order to combine the signal-25s with the broadcast signal. The method also requires a large amount of work and work." to deliver the listening devices to the data collection site and also • · · * a lot of work to decrypt the data of the 2000 listening devices.

The object of the present invention is to provide a new type of method for conducting a listener survey of radio stations, which avoids the problems associated with known solutions.

This object is achieved by the method according to the invention, which is characterized in that in the method mi-: ··; The total number of listeners of the radio stations is detected by detecting the leakage radiation signals of the local oscillators of the radio receivers of the vehicles passing the measurement point 3 98022 the frequency of the leakage radiation signal includes information that the radio receiver of the vehicle in question was tuned to the frequency of that radio station, and that the method is such that information obtained by detecting leakage radiation signals to which radio station the vehicle radio receiver was tuned is stored as a time-dependent signal.

The apparatus according to the invention is characterized in that the apparatus or at least its antenna means is located in the vicinity of the vehicle roadway, the apparatus comprises means for , and that the apparatus further comprises computing means 25 connected to the radio receiver unit for incrementing the measurement result of the total listener of each radio station when the frequency of the local oscillator leakage signal received by the radio receiver unit includes listening on the vehicle.

ί.Ι.ϊ 30 The invention is based on the technical infrastructure of observable radio receivers. Practically everyone. ···, the radio receiver works in the so-called super receiver principle.

In such a radio receiver, each radio station to be listened to corresponds to its own frequency of the local oscillator signal, which is 4 98022 kio as commonly used receivers. In general, this frequency of the local oscillator signal is the frequency of the radio station listened to by the radio receiver plus an intermediate frequency, which is usually 10.7 MHz. This local oscillator signal also leaks slightly outside the receiver via the antenna of the radio receiver. According to the applicant's observations, the field strength of the leakage radiation from the local oscillator is detected to be large enough even more than 10 meters away from the vehicle.

10 The monitoring of the leakage radiation signal of the local oscillator of the radio receiver is known per se, for example in the monitoring of illegal police radio receivers. Additionally, the technology is used, for example, 15 to establish military intelligence counterparty radio traffic channels to the listening frequency. However, these applications do not involve a listener survey that monitors and compares the total listener numbers of several public radio stations. The methods and equipment used in said applications are not suitable for performing listener surveys of radio stations.

The basic idea of the present invention is to exploit in a new way an existing phenomenon known per se, i.e. the leakage radiation of the local oscillator of the radio receiver, so that by calculating and classifying the received leakage radiation signals, a · · * 'is generated. the number of listeners on radio stations. The object of the invention is to monitor the radio listening of passing car traffic.

• · · * · * ’The aim is to find out what the mutual market share of different radio stations is for listeners. With the help of the method, it is possible to find out how many vehicles listening to a radio station • • · · · are detected passing the equipment in a certain unit of time.

The method according to the invention achieves several advantages. The method is passive for the listener of the radio station 35 and therefore does not require any action on the part of the listener, and as a result the results are absolutely objective. The listener in the vehicle does not even notice that he was observed as to which radio station was being listened to in the vehicle. The invention utilizes the existing movement, i.e. the normal movement of the vehicles on the carriageway, whereby the measurement results are generated automatically when the vehicle passes the measuring point. At the same time, the measurement results are also saved automatically, so that no separate large-scale measures are required to decrypt the measurement results. The method and apparatus are also useful in that they do not require any signal signals to be provided on the transmission signal of the radio stations. The method can easily and quickly reach a large number of measurements, which statistically improves the reliability of the results. There does not have to be a very busy section of road through which, for example, 2,000 vehicles pass by a radio station pass in a short time. In the invention, listener research is performed on vehicle radio receivers. With a view to developing a radio station program 20 for a vehicle, in practice the car is the best possible place to conduct a listener survey, because in a car the listener is the fastest and easiest to change channels if the program does not please. inventions; the method and apparatus according to the invention provide reliable real-time information corresponding to the actual '·' "25 situation.

• · · • ·

The method and apparatus according to the invention provide a solution for obtaining the feedback required for the development of the program profile of a radio station in an easy, reliable, fast and easily reproducible manner. Real-time; Thanks to 30, the information can be used in conjunction with a "driving list" of programs to develop a program profile of a radio station so that the listener's "···" position of the station can be improved. Similarly, one can study the change in the popularity of competing positions and its correlation with software.

• Of the 35 vehicles in motion, passively measured from a human point of view, 6,98022 is the most immediate and truthful feedback and also includes information on the listener's response to the internal structure of the program. By comparing, for example, the program activity defined for the different times of the day 5 and the simultaneous information about the listener's share, the popularity of the station can be maximized, because the various factors influencing the popularity can be determined. Changes in lunar numbers and their directions can be seen immediately. In addition to the popularity of one's position, one immediately sees the situation of competitors and this can also be used. The method and apparatus according to the invention are primarily suitable for the development of radio station software and for supporting the planning and implementation of advertising sales.

The invention will now be described in more detail with reference to the accompanying drawings, in which Figure 1 shows a first embodiment of the invention, Figure 2 shows a second embodiment of the invention, Figure 3 shows a third embodiment of the invention, Figure 4 shows a block diagram of a radio receiver unit according to the invention, Figure 5 shows a normal super type a block diagram of a radio receiver, Fig. 6 shows an internal system of the apparatus according to the invention. 25 to the tunnel, «4 Fig. 7 shows the envelope formed by the leakage radiation of the local * oscillator signal passing the measuring point ♦» • «· * raa, Fig. 8 shows the leakage radiation of the local-oscillator signal passing the measuring point and the background interfering radio envelope, Fig. 9 shows the reception of a plurality of antenna means. : ground sum signal.

Initially, referring to Fig. 5, a block diagram of a normal FM-35 range super receiver A is shown. vehicles

II

The block diagram of the radio receivers A of 7 98022 is similar to Fig. 5. The radio receiver comprises a preamplifier consisting of an amplifier 1a and a filter Ib, a local oscillator 2, a mixer 3, an intermediate frequency filter 4, an il-5 ground 5, and an antenna 6. The preamplifier consists of an amplifier 1a rated for the desired frequency range (FM frequency range 87.5 to 108 MHz) and from filter Ib. The signal of the local oscillator 2 is mixed in the mixer 3 with the radio frequency 10 signal coming from the antenna 6 via the preamplifier 1a, ib, resulting in an intermediate frequency signal which is filtered by the intermediate frequency filter 4. The frequency F (loc) of the Pai oscillator 2 is MHz The frequency 10.7 MHz is a commonly used so-called intermediate frequency. The intermediate frequency signal is passed to the detector 5, after which the desired audio frequency output signal 7 is obtained. The signal of the local oscillator 2 leaks slightly backwards in the receiver through the preamplifier 1a, ib primarily through the antenna 6. This leak is noticeable as a weak fixed-frequency radio-20 chip above the 10.7 MHz listening frequency. This signal can normally be measured from a distance of more than 10 meters. In Figures 1, 3 and 5, the leakage radiation is indicated by the marking B.

Detection of leakage radiation B of local oscillators from among possible interference signals is possible because it is fixed frequency and has a signal format of .j. such that the field strength of the signal increases rapidly 4 «· 4 / ··. up and down quickly in the same way down unlike «i« with interference signals.

. Referring to Figures 1-3, on the road 10, vehicles 11-13 proceed. Each of the vehicles comprises a radio receiver A of the 4 · 4 * type shown in Fig. 5, the local oscillator. the radiators 2 emit leakage radiation B through the antennas 11a-13a of the radio receivers 11-13. Antennas 11a- '. 13a correspond to the antenna 6 of Fig. 5. In the vicinity of the carriageway 10 there is a measuring device 14 comprising a radio receiver unit 15, an antenna means 16 and a cable 17 between the radio receiver unit 15 and the antenna means 16. The function of the radio receiver unit 15 is to detect receivers -5 den 2 leakage radiation signals B from the antennas 11a-13a of the radio receivers of the vehicles 11-13. In addition, Figs. 1-3 show computing means 18 which are connected to a radio receiver unit 15 by a cable 19. The computing means 18 are most preferably formed, for example, by means of a microcomputer 10. The function of the calculating means 18, such as a microcomputer, is to count, i.e. register, pulses from the radio receiver unit 15, which in turn depend on which frequency local oscillator leakage signal B the antenna means 16 receives as a recording. In all Figures 1-3, the apparatus also comprises a communication terminal 20, which may also be implemented on the same microcomputer.

Next, it is assumed that there are three radio stations that can be heard at the location in question and, more specifically, at the measurement location in question, namely radio stations R1, R2 and. R3. Assume that the transmission frequency of the radio station R1 would be 90 MHz, the transmission frequency of the radio station R2 would be 95 MHz, and the transmission frequency of the radio station R3 would be 100 MHz. The intermediate frequency of radio receivers is normally 10.7 MHz, so if the driving • · ·

· * * I advise, for example, the vehicle 11 radio receiver A

listening to the radio station R1, then the frequency of the local oscillator 2 of the radio receiver A of the vehicle 11 ra-30 is • · «·. · · 100.7 MHz, which is then also the frequency of the leakage radiation B of the local oscillator 2. If the radio station R2 of the vehicle 11 is listened to by the radio station R2, then the frequency of the local oscillator 35 2 of the radio receiver A of the vehicle 11 is 105.7 MHz, which is then also the local oscillator.

II

9 Frequency B of the leakage radiation 2 of the 98022 capillator. If the radio station R3 of the vehicle 11 is listened to the radio station R3, then the frequency of the local oscillator 2 of the radio receiver A of the vehicle 11 is 110.7 MHz, which is then also the frequency of the leakage radiation B of the local oscillator 2.

In the method according to the invention, the total number of listeners of radio stations R1, R2 and R3 (total number of vehicles in which the station is listened to) is measured by detecting at certain frequencies such as 100.7 MHz, 105.7 MHz and 110.7 MHz, which depend on the frequencies 90 MHz, 95 MHz and 100 MHz of the radio stations R1, R2, R3 to be detected. Thus, the dependence means that the leakage radiation signals B of the local oscillators 2 of the radio receivers A of the vehicles 11-13 received by the radio receiver unit 15 of the equipment are 10.7 MHz higher than the transmission frequencies of the radio stations received by the vehicle radio receivers.

In calculating the number of listeners, the measurement result of the number of listeners of each radio station R1, R2, R3 is increased when the frequency of the leakage signal of the local oscillator 2 of the receiver 11-13 of the vehicle 11-13 passing the measuring point is received by the radio receiver unit 15 • * that the radio response of that vehicle. receiver A was tuned to the frequency of that radio station R1, R2, R3 • · · • ·; * · 30. If the radio receiver unit 15 receives 100.7 MHz of leakage radiation B from the local oscillator of the vehicle radio, then the total listening position of the radio station R1 from the measurement result of the radio station R1 is increased in the calculation. If the radio receiver unit 15 receives 35 leakage radiation B at a frequency of 105.7 MHz from the local oscillator of the radio receiver of the vehicle 10 98022, then in the calculation the measurement result of the total number of listeners of the radio station R2 is increased. If the radio receiver unit 15 receives leakage radiation B 5 from the local oscillator of the vehicle radio receiver 110.5 MHz, then the measurement result of the total number of listeners of the radio station R3 is increased in the calculation. Strictly speaking, the total number of listeners in this context does not mean so much the number of people listening to a particular radio station, but the number of vehicles that have passed the measurement point by 10 listening to a particular radio station. The measurement result of the number of listeners is increased in such a way that the radio receiver unit 15 gives a pulse to the calculation means 18, i.e. for example a microcomputer, where the pulse increases the numerical value of the memory location corresponding to the detected radio station 15.

In a preferred embodiment, the method operates by determining the relative listener shares of several radio stations R1, R2, R3 on the basis of measuring and calculating the frequency-dependent local oscillator signals B of the radio station R1, R2, R3 listened to in the vehicle.

In a further preferred embodiment, the operation is such that the information about the listener numbers and / or listener parts measured by the method is transferred to at least one of the radio stations R1, R2, R3 whose listener numbers are measured.

1 .. 25 Referring to Fig. 2, the apparatus comprises, for example, a data processing device 21 located in a radio station, which may be, for example, a microcomputer. In addition, the apparatus provides a transmission link 22 between the measurement site and the radio station and modems 23 for transmitting measurement data to the radio station. The measured data can be processed at the radio station, for example • · * * by means of standard statistical software on a microcomputer 21, whereby it is obtained in an illustrative form. An illustration of the data is shown in Figure 2 by Figures 24-26. Diagram 24 shows the relative listener distribution of three radio stations R1, R2, "35 R3. Figure 25 shows the listener numbers of radio stations R1, R2, R3 as a function of time. Figure 26 shows the listener readings of one radio station R1 as a function of time. Measurement data can be transferred. also to a non-radio station, for example to a company providing listener research services, but at some point the measurement data in one way or another will end up in the least favorable way for the radio station as well, because it is the most useful for the data.

The information on which radio station the receiver of the vehicle radio-10 was tuned to is most preferably stored as a time-dependent signal detected in Figures 25 and 26, since the temporal behavior of the listener numbers and listener portions can then be monitored.

In a preferred embodiment, the listening of radio stations 15 is performed in a frequency range consisting of one or more entities, which is completely or partially comprehensive, and the lowest frequency of which is at least as low as the frequency of the lowest frequency station plus at least one frequency of the radio receiver. higher than the frequency of the highest frequency radio station plus the intermediate frequency of the local oscillator of the radio receiver. In the case of radio stations R1, R2 and R3, the lowest frequency would be at least as low • · · · ... · 25 as the frequency 100.7 MHz and the highest frequency would be at least as ♦ high as the frequency 110.7 MHz.

In the preferred embodiment of the method, the radio receiver unit 15 receives the radio receiver of the vehicles. leakage signals of the local oscillators of the receivers in narrow ♦ · · 30 bandwidths around the frequencies of the local oscillator signals ♦ · · i.e. in the vicinity of the frequencies 100.7 MHz, 105.7 MHz and 110.7 MHz. In this way, the possibility of errors is reduced.

. : In the embodiment of Fig. 3 there are several (2 pieces) antenna means 16 and an adder means 27. In a preferred embodiment, the leakage radiation signals B of the local oscillator 2 of the vehicle radio receiver A are detected by a plurality of antenna means 16, the received signals of which are generated the listening position of the radio station is increased. The common signal S is shown in Fig. 9. The use of a plurality of antenna means 16 reduces the probability that an interference signal could be mistaken for a local oscillator leak signal. The common signal S is a special signal so much that the occurrence of such an interference signal is highly unlikely. From the common signal S, interference 200 due to propagation delays can be detected, the existence of which facilitates error-free detection.

Fig. 6 shows the arrangement of the apparatus 15, 16 according to the invention in a tunnel 28. In a preferred embodiment, the detection is performed in a tunnel 28 comprising a vehicle 11 travel path, such as an underpass tunnel, transit tunnel or other similar interference-free environment 20, as the chances of error are further reduced.

. . In Fig. 2, the apparatus also comprises sensor means • '29, such as an induction loop for detecting whether there is a vehicle in the measuring area. In this case, in the method ra- ·. In addition to the leak signal detection by the diode receiver unit 15, the sensor means 29 detects whether there is a vehicle in the measurement area, and the measurement result of the radio station listener is only increased when it is further detected that there is a vehicle in the measurement area. Like this . 30 again, sources of error are eliminated. Embedded in the road • • · ·. ♦ j ·. the line means 29 is connected to the radio receiver unit 15 by a game 29a.

Figures 1-3 show a communication terminal 20. In a preferred embodiment, the method further comprises a special observer on the special road 13 98022 storing additional information related to the vehicle and / or persons at the measurement site, and that this additional information is connected to its information. with which station R1, R2, R3 the frequency of the vehicle radio receiver A was tuned. The measuring point thus has a person who, for example from the keyboard 20 of the microcomputer 18, gives additional observations such as whether the vehicle was male or female, whether the person was young or old and whether the vehicle was cheap or skull.

In Fig. 2, the apparatus preferably also comprises a camera means 30, which is connected to the radio receiver unit 15 by means of a cable 31. In a preferred embodiment, the method further comprises recording vehicles passing the measuring point by means of the camera means. The resulting video recording is connected to the information to which radio station the vehicle radio was tuned. In this case, information about what position was listened to in the vehicle and information about what kind of car it was and what kind of people were sitting there can be stored connected to each other.

Referring further to Figure 2, in a preferred embodiment, the apparatus comprises information display means 32 connected by a cable 33 to a radio receiver unit '·' <15. In a preferred embodiment, the leakage signal of the vehicle radio receiver oscillator 1: 25 is detected by the radio receiver unit 15. ♦ · enact information display means 32 such as a billboard or other similar information display means. For example, if the radio receiver unit 15 detects a frequency of 100.7 MHz, then it is a frequency of 90 • · · ·. * MHz from a functioning radio station R1, in which case the advertising message • · could be, for example, a thank you to the radio station for listening to that station. If the vehicle is moon- '. another position such as R2 or R3,. . 35 then the billboard 32 would instruct to change the radio ---- ... Γ "98022 14 to the frequency R1 of the station. This solution adds value to the invention. If the invention is to be applied specifically to the activation of the information display means 32, calculation means 18 and 5 may not necessarily be required. than the monitoring of a minimum of one leakage frequency.

In a preferred embodiment, in order to eliminate interference signals, the method mainly detects signals that are substantially symmetrical with respect to their amplitude peaks. This is because the leakage signal B of the local oscillator 2, which bypasses the linear advancing movement of the measuring point as the vehicle progresses, is of such a shape. The radio receiver 15 can be designed so that it responds only to signals in the form shown above, i.e. to a signal rising and falling around its amplitude peak. The envelope curves shown in Figures 7 and 8 are signals of the shape shown above.

The radio receiver unit 15 is a device which detects several monitored local oscillator frequencies, i.e. now the frequencies 100.7 MHz, 105.7 MHz and 110.7 MHz, which thus correspond to the transmission frequencies of the radio stations R1, R2 and R3 plus the intermediate frequency 10.7 MHz. The detection of the leakage radiation B 25 of the local oscillator signals, i.e. the local oscillators 2, can be realized either by one receiver, which quickly switches from one channel to another, i.e. the so-called. with a scanner or several ♦ · «* · * * parallel receivers according to Figure 4. Figure 4 shows a block diagram of a diode-receiver unit 15 capable of monitoring three different positions R1, R2, R3. The receiver unit 15 of Figure 4 comprises three parallel receivers 151, 152 and 153. The first receiver part 151 of the radio receiver unit 15 is designed to monitor the frequency 100.7 MHz, i.e. practically listening to the radio station R1 '35 in the vehicle. The second receiver part 152 of the radio receiver unit 15 98022 is implemented in such a way that it monitors the frequency 105.7 MHz, i.e. in practice listening to the radio station R2 in the vehicle. The third receiver part 153 of the radio receiver unit 15 is implemented in such a way that it monitors the frequency 110.7 MHz, i.e. in practice listening to the radio station R3 in the vehicle.

The structure of the first receiver portion 151 of the radio receiver unit 15 will be described below. The reference numbers shown are also the same for the other receiver parts 152 and 10 153. The first receiver part 151 of the radio receiver unit 15 comprises a preamplifier connected to the antenna means 160, comprising a preamplifier 161a and a filter 161b tuned to the local oscillator leakage signal frequency 100.7 corresponding to the radio station R1 that the receiver section 151 receives frequencies in a narrow bandwidth around 100.7 MHz of that frequency. In addition, the first receiver section 151 comprises a local oscillator 162, a mixer 163, an intermediate frequency filter 164, a detecting means 165, a filter 166, 20 also having a pulse detection means 167. In this connection, it is noted that the local oscillator 162 of the receiver section 151 of the radio receiver unit 15 to the local oscillator 2 of the vehicle radio receiver A in Figure:: 25 5.

• * · ··· In Figure 4, the apparatus radio receiver unit 15

• • M

the frequency of the local oscillator 162 of the receiver section 151 is mixed with the frequency received in the mixer 163. i.e., from antenna 160 to preamplifier 161a, 161b, which is thus the frequency of the leakage radiation signal of the vehicle radio receiver, which: thus, in the case of the first receiver portion 151, is 90 MHz from the transmission frequency of the radio station R1. dependent frequency 100.7

Mhz. The result is an intermediate frequency which is separated by an intermediate-frequency filter 164. The intermediate-frequency filter 164 has a detector means 165, which is most preferably an AM detector. The output of the detector means 165 provides an envelope of the transmission at the desired frequency (now 100.7 MHz), such as envelope 170 or envelope 5 180, as shown in Figures 7 and 8. The resulting signal is filtered as a suitably sized filter 166 to reduce potential interference.

The envelope 170 of Figure 7 shows only the detected bypassed local oscillator signal B at the frequency of 100.7 MHz in question. The pulse duration depends on e.g. the type of hardware antenna 16 and the speed of the vehicle. Typically, the pulse duration is, for example, 1 second. The envelope 180 of Figure 8 includes the interaction between the background interfering radio source and the local oscillator-15 ris signal B passing the measurement site. Since the potential interfering transmission in the FM band is generally frequency modulated, its amplitude is constant and causes the bottom level 190 of the envelope to rise. The pulse detection means 167, like the detection circuit, is implemented so as to be able to eliminate this rise in the bottom level and to detect the presence of the envelope pulse according to Fig. 7. The elimination of the base plane takes place, for example, by detecting the base plane 190 by the sensor means 167 and setting this as a reference level for detecting the pulse. The output of the detection circuit 167 comprised by the first receiver section 151 • · ***** of the radio receiver unit 15 of the apparatus ... 25 pulses 300 • · · ••• I whenever the receiver section 151 detects a measuring point at the relevant V * frequency (100.7 MHz) bypassing the local oscillator signal B. Correspondingly, a pulse 300 is obtained from the output of the detection circuit 167 operated by the second receiver section 152 of the radio receiver unit 15 of the apparatus sj: 30 whenever the receiver section 152 detects a local oscillator signal passing the measurement location at the frequency (105.7 MHz). Correspondingly, a pulse is obtained from the output of the detection circuit 167 comprised by the third receiver section 153 or 178080 of the radio receiver unit 15 of the apparatus 35 whenever the receiver section 153 detects a local oscillator signal B passing the measurement location at the frequency (110.7 MHz). Each detected local oscillator signal , which indicates which radio station was listened to in the vehicle in question. These pulses are stored in memory and used to calculate total listener numbers, for example by means of a microcomputer 18 or the like 10. The detection of pulses can also take place, for example, with a microprocessor by means of a suitable algorithm.

Referring to Fig. 5, due to the structure of the mixer in the vehicle radio receiver A, the signal of the local oscillator 2 has, in addition to the fundamental frequency, also its harmonic frequencies, which are also measurable. The use of these harmonic frequencies in the solution according to the invention is also possible.

Although the invention has been described above with reference to the examples according to the accompanying drawings, it is clear that the invention is not limited thereto, but can be modified in many ways within the scope of the inventive idea set forth in the appended claims. If there are many radio stations to be detected, for example 10, then the radio receiver unit 15 is implemented 25 in such a way that it can monitor the leakage signal of 10 different frequencies of the local • · * ··· * additional oscillator.

• · i • · «· • *« f 4 · i «t •» «» ► · · «· · · · • ·

Claims (18)

Method for conducting listener examination for radio stations, characterized in that in the method the total number of radio stations is measured by observation of leakage signals from local oscillators in the measuring station passing vehicle radio receivers substantially simultaneously on a plurality of predetermined frequencies, which frequencies for the observed radio stations, and when calculating the listener count, the measurement result for each radio station's listener number is increased when the frequency of the local oscillator leakage signal in a measuring station passing vehicle radio receiver includes information that the radio receiver of the vehicle in question is tuned to so that the information obtained by observing the leakage radiation signals about which radio station the radio receiver of the vehicle was tuned is recorded as a time dependent signal. 20 2. A method according to claim 1, characterized in that relative listener proportions for a plurality of radio stations are determined on the basis of measurement and calculation of the frequency oscillator signals dependent on the frequency of the radio station being listened to in the vehicle. ···· 25 3. A method according to claim 1 or 2, characterized in that the radio stations' listening is carried out on one or more whole or part of the frequency band formed which is fully or partially covered, and which is the lowest frequency range. at least 30 equal to the frequency of the radio station with the lowest frequency increased by the intermediate frequency of the local oscillator in the vehicle's radio receiver, and which frequency range is the highest frequency at least as high as the frequency of the radio station with the highest frequency. increased by the intermediate frequency of the local oscillator in the vehicle's radio receiver Il 23 98022 4. A method according to claim 1 or 2, characterized in that the data relating to the listener number and / or listener shares are fed to the method to at least one of the radio stations whose listener number is measured. Method according to claim 1 or 2, characterized in that the leakage radiation signals of the local oscillator in the vehicle's radio receiver are observed with a plurality of antenna means and a common signal is formed by the signals which they have received, and when it is observed, the measurement result for the radio station's listening number is increased. Method according to claim 1, characterized in that the observation is carried out in a tunnel on the vehicle's progress route, such as a subway tunnel, a passage tunnel or other corresponding noise-free environment. Method according to claim 1, characterized in that the method is further observed with a sensor means if a vehicle is in the measuring range, and that the measurement result of the radio station listener number is increased only when a vehicle is observed in the measuring area. 8. A method according to claim 1, characterized in that the method further processes such that a special observation person with special communication terminals registers additional information about the vehicle and / or the persons present at the measuring station. · · Located therein, and that these additional information *: * is combined with the information on which station frequency • · · · the vehicle's radio receiver was tuned. «30 Method according to claim 1, characterized in - t e c k n a t in the process of further recording the measuring station of passing vehicles with a camera means, and of the thus generated image registration being associated with the information on which radio station of the vehicle's radio; 35 recipients were reconciled. 24 98022 10. A method according to claim 1, characterized in that the observation of the local oscillator leakage signal in the vehicle's radio receiver is used for activating an information producing means such as e.g. a billboard or other corresponding information agency. 11. A method according to claim 1, characterized in that substantially signals which are substantially symmetrical relative to their amplitude peak are observed for the elimination of noise signals. 12. A method according to claim 1, characterized in that AM detection is used for the elimination of interference signals. Apparatus for conducting a listening station for radio stations, comprising a radio receiver unit (15, 151-153) and an antenna means (16) connected thereto, characterized in that the device or at least its antenna means (16) is arranged in the vicinity of the vehicle (11-13) executable (10), the device comprising means for substantially simultaneous observation of leakage radiation signals (B) from local oscillators (2) in the antenna means (16) passing vehicle radio receivers at a plurality of predetermined frequencies which is dependent on the frequencies of the observed radio stations, and that ···. The apparatus further comprises the computational means (18) connected to the radio receiver unit ··· V · (15) for increasing the measurement results of each radio station (R1, R2, R3), the total cord - # <* 15) received frequency signal: the leakage radiation signal (B) of the local oscillator comprises information about listening to the radio station in question. . ·. (R1, R2, R3) in the vehicle (11-13). • · ·. * ··. Device according to claim 13, characterized in that the radio receiver unit (15) comprises an AM detector (165). ; ; 35 Device according to claim 13, characterized in that the device comprises a plurality of antenna means (16) connected via an adder means (27) to the radio receiver unit (15). Device according to claim 13, characterized in that the device comprises a sensor means (29) for observing whether vehicles (11-13) are in the measuring range. Device according to claim 13, characterized in that the device comprises data transfer means (22, 23) for transmitting the measurement results from the measurement site. Device according to claim 13, characterized in that the device further comprises an information means (32), such as an advertising sign, and that the radio receiver unit (15) is coupled to control the activation of the information means (32). · Ψ · · ♦ • (♦ ((((((((((((((((