NO345505B1

NO345505B1 - Radio channel identification device and method.

Info

Publication number: NO345505B1
Application number: NO20171600A
Authority: NO
Inventors: Jon Olavsson Neset
Original assignee: Anywave As
Priority date: 2017-10-06
Filing date: 2017-10-06
Publication date: 2021-03-15
Also published as: AU2018346372A1; EP3692659A1; NO20171600A1; AU2018346372B2; WO2019068873A1

Description

The invention regards a radio channel identification device and an adapter for converting DAB signals into FM signals.

Digital radio, for example Digital Audio Broadcast (DAB) technology, enables large numbers of radio stations to be received terrestrially on special digital receiver systems. Recently also internet radio has been popular, as it enables the user to listen to a very large number of radio channels provided he has internet connection. The below discussion is based on DAB to FM radio signal conversion, but will be similarly valid for internet radio or other broadcast audio signals.

Along with the audio signal, data identifying the channel name, content information etc. is also broadcast so that it can be displayed on a display of the reader. The signal transmission is generally considered more robust as it does not suffer from the gradual fading experienced by analogue radio technologies.

The DAB system undoubtedly offers numerous technical advantages as compared with the conventional FM receivers, e.g. in radio devices or as FM tuner devices etc., so that it may be anticipated that the DAB system will, in the near future, be introduced with full geographical coverage, and this will take place within a comparatively short period. In Norway for example, the DAB system is scheduled to have full coverage during 2017, and following this, the nationwide broadcasters close down their FM transmissions. However, this would mean that, following the introduction of this DAB system, a large number of conventional FM receivers will suddenly become useless, since FM radio signals would no longer be transmitted, and the existing FM receivers would be replaced with DAB appliances. Quite apart from the enormous environmental pollution caused by the disposal of the existing FM receivers, high costs for consumers would be involved as a result of the procurement of the new DAB appliances, which is all the more significant when the static domestic audio systems, which are costly per se, are taken into account. One further aspect that induces consumers to hold on to an existing radio receiver is the fact that, in the case of matching components (such as a tuner, preamplifier, output amplifier, cassette deck, CD player etc.) in existing domestic systems, exchanging a tuner component for a different one, which would then no longer match the remaining components for aesthetic or visual reasons, is not undertaken willingly.

New vehicles are often provided with DAB as standard, but older vehicles most often has analog radio and, as an optional upgrade feature, the additional cost tends to deter take-up. For older cars, replacement of the original head unit tends to be expensive also, and inconvenient, requiring technical specialists. Retro-fit solutions exist, and are often preferred, but have drawbacks. One method is to attach a DAB antenna to the windscreen (in the manner of a stand-alone satellite navigation device) which is connected to a stand-alone control unit also connected to the windscreen or dashboard. Power is provided via the cigarette lighter socket to the control unit and transmission of the received DAB signal is via a FM transmitter to a selected free frequency manually tuned at the in-situ head unit, or plugged into an Aux-In port if one is available. In general, retrofit solutions require a special DAB aerial, dedicated control panel, and connection to the car's battery via the cigarette lighter or via the internal loom.

One particularly annoying feature of such retro-fit solutions, is that the radio channel must be selected at the DAB unit, as the FM unit is solely used for producing the sound. Integrated channel selectors in the steering wheel will also not work, and the selection of channel will be a disturbance for the driver during the drive. The same problems as described above are valid for other kind of conversion of audio signals as well, for example converting FM to AM radio signals, or in particular when converting internet radio signals to FM signals.

EP 2495895 regards a DAB-FM converter for cars that converts DAB signals to standard FM signals. The converter can be controlled by systems already present in the car, for example the steering wheel.

US2008212785 describes a DAB-FM converter which has the ability of detecting a chosen FM frequency and tune the DAB receiver based on the detected frequency. The Frequency is detected by means of, for example, an additional FM receiver.

GB2475580 and EP946011 regards prior art solutions related to radio.

There is thus a need for an adapter for converting one type of audio signals to another type of audio signals which alleviates the above mentioned drawbacks, and in particular a radio channel identification device which enables the use of channel selection on the FM device, or other audio receiver.

The object of the invention is to provide an adapter for converting audio signals, and a radio channel identification device, which enables the consumer to continue the use of his existing audio receiver while listening to any kind of audio transmission.

The object of the invention is achieved by means of the patent claims.

In one embodiment, a radio channel identification device comprises an audio signal transmitter, an audio signal receiver and a control unit connected to the audio signal receiver. The audio signal transmitter can transmit an audio signal on at least two predetermined radio frequencies, and the control unit is adapted to detect if the audio signal receiver receives an audio signal and determine on which of the predetermined radio frequencies the audio signal was transmitted.

The audio signal can be an audible or non-audible signal, ie. it has a frequency which is in the audible range, for example 20-20000Hz, or in the non-audible range, such as above 15000 Hz.

The radio channel identification device transmits an audio signal on any of the predetermined frequencies. There may be many predetermined frequencies, for example corresponding to the number of radio channels the user wishes to be able to select from when using a radio. In one embodiment, the audio signal is transmitted on several of the predetermined frequencies. The control unit may comprise a memory device storing information concerning the mutual correspondence of channels, for example the mutual correspondence of DAB channels and FM channels. In this latter case, the user has for example selected that the FM receiver should broadcast channel 1 and channel 2, which corresponds to the same channel 1 and channel 2 of the DAB broadcasting. The memory device then store the correspondence between channel 1 in the FM receiver, ie. which frequency is dedicated to channel 1, and channel 1 of the DAB broadcasting.

In one embodiment, the control unit is connected to the audio signal transmitter and is adapted to control on which radio frequency the audio signal is transmitted.

The control unit may be connected to the audio signal transmitter and controls the audio signal to be transmitted on each predetermined radio frequency sequentially, ie. the audio signal is first transmitted on one frequency, then on the next frequency, etc., and then starting with the first again. In another embodiment, the audio signal may be transmitted on each predetermined radio frequency simultaneously, where each radio frequency transmits an audio signal with a unique audio signature. In yet another embodiment, the audio signal is transmitted on each predetermined radio frequency except for one, which silent radio frequency is the frequency of interest, ie. corresponding to the channel the user wants to listen to.

The control device may be connected to the audio signal transmitter and adapted to control the frequency and/or other feature of the audio signal.

The radio channel identification device may be used in an adapter for converting DAB signals into FM signals and for transmitting the FM signals to an FM receiver. In one embodiment, such an adapter comprises a radio channel identification device as described above in order to identify which radio channel the user wants to listen to. The adapter also comprises a DAB receiver (or other audio signal receiver), which DAB receiver are equipped with an antenna input, FM modulator means for generating an FM signal, an FM signal transmitter for transmitting the generated FM signal to the FM receiver, and control means connected to a channel setting input of the DAB receiver means. The DAB receiver is then designed to be tuned on the basis of the signal delivered to the channel-setting input from the control means.

The invention will now be described in more detail, and by means of an example illustrated in the accompanying figures.

Figure 1 illustrates schematically an adapter for converting DAB signals into FM signals, comprising a radio channel identification device.

Figure 2 illustrates memory means for storing information concerning the mutual correspondence of DAB channels and FM channels comprised in the control unit.

The adapter 10 for converting DAB signals into FM signals and for transmitting the FM signals to an FM receiver comprises a DAB receiver and FM modulator means 21 for generating an FM signal based on the received DAB signal, an FM signal transmitter 22 for transmitting the generated FM signal to the FM receiver 17, and control means 25 connected to a channel setting input of the DAB receiver means. The DAB receiver 21 is equipped with an antenna input 11 for receiving the DAB signal from the radio station provider, and/or an antenna input 12 for other audio signals.

The adapter further comprises a radio channel identification device for identifying which channel the user wants to listen to. In use, the user will then be able to select a channel on his FM radio apparatus 17, which comprises the FM receiver. The channel identification device will identify which channel the user has selected and tune the DAB receiver/FM modulator 21 to this channel. The DAB receiver may be designed to be tuned on the basis of the signal delivered to the channel-setting input from the control means 25.

The radio channel identification device comprises an audio signal transmitter 24, an audio signal receiver 18, and a control unit 25 connected to the audio signal receiver18. The audio signal transmitter 24 can transmit an audio signal on at least two predetermined radio frequencies, and the control unit 25 is adapted to detect if the audio signal receiver receives an audio signal and determine on which of the predetermined radio frequencies the audio signal was transmitted.

The audio signal transmitter 24 transmits the audio signal to the radio apparatus 17 which provides a sound through its speakers 27. The audio signal receiver 18 registers the sound and transmits the audio signal to the control unit 25 for processing.

The audio signal may be transmitted on any of the predetermined frequencies in the FM broadcasting range, which for example is in the frequency range from 65 MHz to 108 MHz. Each predetermined frequency, (FM channels) has assigned a mutual corresponding DAB channel which is stored in a memory in the control unit 25. The control unit 25 causes the audio signal to be transmitted on each of the predetermined frequencies sequentially, ie. first an audio signal is transmitted on the first predetermined frequency, then an audio signal is transmitted on the second predetermined frequency, etc. If the FM channel corresponding to the first predetermined frequency is selected by the user, the control unit 25 registers the audio signal, analyzes the signal and determines that it was transmitted on the first predetermined frequency. The Control unit 25 then looks up in the registered mutual assigned DAB channels and selects the correct DAB channel which the user will listen to. The DAB signal of this channel is then modulated to generate an FM signal, and transmitted by the FM signal transmitter 22 to the FM receiver 17.

The control unit may control the audio signal to be transmitted on each predetermined radio frequency sequentially, and when the signal, ie. a sound is registered, the control unit knows which frequency is selected by the user.

As an alternative, there may be transmitted a sound signal on all predetermined frequencies but the one of interest, ie. the frequency selected by the user does not carry any sound signal. The control unit will then identify which frequency is not carrying any transmitted signal, and this the DAB channel assigned to this frequency is selected for FM modulation and transmittance to the radio apparatus 17.

Figure 2 illustrates a detail of figure 1, specifically the memory means of the control unit for storing information concerning the mutual correspondence of DAB channels, internet radio channels and FM channels comprised in the control unit.

Claims

1. Radio channel identification device comprising

- an audio signal transmitter (24) which can transmit an audio signal on at least two predetermined radio frequencies,

- a speaker (27), adapted to transmit a sound according to a frequency selected by a user,

- an audio signal receiver adapted to register a sound,

- and a control unit (25) connected to the audio signal transmitter (24) and the audio signal receiver,

where the control unit (25) is adapted to control on which radio frequency the audio signal is transmitted, to detect if the audio signal receiver receives a sound and determine on which of the predetermined radio frequencies the sound was transmitted.

2. Radio channel identification device according to claim 1, where the control unit (25) controls the audio signal to be transmitted on each predetermined radio frequency sequentially.

3. Radio channel identification device according to claim 1, where the control unit (25) controls the audio signal to be transmitted on each predetermined radio frequency simultaneously, where each radio frequency transmits an audio signal with a unique audio signature.

4. Radio channel identification device according to claim 1, wherein memory means for storing information concerning the mutual correspondence of one audio signal channel and another audio signal channels are assigned to the control unit.

5. Radio channel identification device according to claim 1, where the control device is adapted to control frequency and/or other feature of the audio signal.

6. An adapter (10) for converting DAB signals into FM signals and for transmitting the FM signals to an FM receiver (17), comprising a radio channel identification device according to any of the previous claims, where the adapter further comprises: a DAB receiver (21), which DAB receiver are equipped with an antenna input, FM modulator means for generating an FM signal, an FM signal transmitter for transmitting the generated FM signal to the FM receiver, and the control unit (25) is connected to a channel setting input of the DAB receiver, wherein the DAB receiver is designed to be tuned on the basis of the signal delivered to the channel-setting input from the control unit.

7. Adapter according to claim 7, where the FM signal transmitter is wireless transmission means.

8. Adapter according to one of the claims 6 or 7, wherein the FM receiver is rated for a reception frequency range from 76 MHz to 108 MHz.

9. Adapter according to one of the claims 6-8, wherein inputting means are assigned to the control unit.

10. Adapter according to claim 6, wherein the FM modulator is arranged to process supplementary information during the FM modulation.

11. An adapter according to one of the claims 6-10, wherein the FM modulator is connected to the control unit in order to transmit supplementary information.

12. Method for radio channel identification comprising

- transmitting an audio signal on at least two predetermined radio frequencies, - receiving an audio signal, and

- detecting reception of an audio signal and determining on which of the predetermined radio frequencies the audio signal was transmitted.

13. Method according to claim 12, further comprising

- receiving a radio signal comprising a number of radio channels,

- selecting one of the received radio channels based on the determined frequency on which the audio signal was transmitted,

modulating the radio signal of the selected radio channel.

14. Method according to claim 13, where the received radio signal is a DAB signal, and the radio signal is modulated to generate an FM signal, and the FM signal is transmitted to an FM receiver.