1. A video signal transceiver having a triax port, a baseband port, a demodulator for converting a HF video signal received at said triax port into a first baseband video signal for outputting at said baseband port and at least one modulator for converting a baseband control signal received at said baseband port into a HF control signal for outputting at said triax port, a fibre-optical port, an optical receiver for converting an optical video signal received at said fibre-optical port into a second baseband video signal, a switch for connecting either said first baseband video signal or said second baseband video signal to a video signal line of said baseband port, and an optical transmitter for transmitting, via said fibre-optical port, an optical control signal derived from said baseband control signal.
2. The transceiver of claim 1, wherein an input of the optical transmitter receives said HF control signal from said at least one modulator.
3. The transceiver of claim 2, further comprising a switch for selectively applying said HF control signal either to said triax port or to said optical transmitter.
4. A video signal transceiver having a baseband port, a triax port, a modulator for converting a baseband video signal received at said baseband port, into a HF video signal for outputting at said triax port and a filter for converting a HF control signal received at said triax port into a first baseband control signal for outputting at said baseband port, a fibre-optical port, an optical transmitter for converting a baseband video signal received at said baseband port into an optical video signal for transmission at said fibre-optical port, an optical receiver for converting an optical control signal received via said fibre-optical port into a second baseband control signal, and a switch for selectively connecting either the first baseband control signal or said second baseband control signal derived from said optical control signal by said optical receiver to at least one demodulator, and said at least one demodulator for converting said output of said switch into a control signal supplied to a control signal line of said baseband port.
5. The transceiver of claim 4, wherein said second baseband control signal from said optical receiver is applied to said at least one demodulator.
6. The transceiver of claim 5, further comprising a switch for selectively applying said baseband video signal either to said modulator or to said optical transmitter.
7. The transceiver of claim 4, comprising signal source detecting means for detecting a signal source connected to said triax port or to said fibre-optical port and for operating the switch so as to establish a signal connection between the baseband port and the one of triax and fibre-optical ports at which the signal is detected.
8. The transceiver of claim 7, wherein the signal source detecting means is adapted to establish the signal connection between the baseband port and a predetermined one of triax and fibre-optical ports if the signal is detected at both the triax port and the fibre-optical port.
9. The transceiver of claim 7, wherein the signal source detecting means comprises a photo-detector connected to said fibre-optical port and judges a signal to be present at the fibre-optical port based on the average optical power received at said photodiode.
10. The transceiver of claim 7, wherein said signal source detecting means comprises carrier detecting means for retrieving a carrier of a modulated signal received at said fibre-optical port and judges a signal to be present at the fibre-optical port based on whether said carrier is retrieved or not.
11. The transceiver of claim 1, comprising signal source detecting means for detecting a signal source connected to said triax port or to said fibre-optical port and for operating the switch so as to establish a signal connection between the baseband port and the one of triax and fibre-optical ports at which the signal source is detected.
12. The transceiver of claim 11, wherein the signal source detecting means is adapted to establish the signal connection between the baseband port and a predetermined one of triax and fibre-optical ports if the signal source is detected at both the triax port and the fibre-optical port.
13. The transceiver of claim 11, wherein the signal source detecting means comprises a photo-detector connected to said fibre-optical port and judges a signal to be present at the fibre-optical port based on the average optical power received at said photodiode.
14. The transceiver of claim 11, wherein said signal source detecting means comprises carrier detecting means for retrieving a carrier of a modulated signal received at said fibre-optical port and judges a signal to be present at the fibre-optical port based on whether said carrier is retrieved or not.
15. The transceiver of claim 14, wherein the fibre-optical port comprises two optical fibre lines, the first one of which is connected to said optical receiver and the second one of which is connected to said carrier detecting means.
16. The transceiver of claim 1, wherein a power supply circuit is connected to said triax port and to an electric line of said fibre-optical port so as to provide electric power to a remote signal source, and a load detecting means is provided for detecting whether an electric load is connected to one of said triax and optical ports and for operating the switch so as to establish a signal connection between the baseband port and the one of triax and fibre-optical ports at which the load is detected.
17. The transceiver of claim 16, wherein the load detecting means is adapted to establish the signal connection between the baseband port and a predetermined one of triax and fibre-optical ports if the signal source is detected at both the triax port and the fibre-optical port.
18. The transceiver of claim 17, wherein said switch is operated by a voltage present at said triax port or at an electric line of said fibre-optical port to establish a signal connection between the baseband port and the one of triax and fibre-optical ports at which the voltage is detected.
19. The transceiver of claim 11 wherein the switch is adapted to establish the signal connection between the baseband port and a predetermined one of triax and fibre-optical ports if the voltage is detected at both the triax port and the fibre-optical port.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A frequency modulation method for imprinting a digital message formed by a sequence of symbols on a set of frequency bands, whereby each symbol is assigned one symbol value out of a defined set of symbol values, the method comprising:
defining at least two symbol transmission channels, each symbol transmission channel being formed by a sub-set of frequency bands selected from the set of frequency bands and each frequency band of a symbol transmission channel being allocated to a symbol value of the set of symbol values in a one-to-one relation, such that the symbol transmission channels differ from each other in at least one frequency band of the sub-set of frequency bands andor in an allocation of a frequency band to a symbol value; and
modulating each of the defined symbol transmission channels successively with a single symbol value of the digital message according to the allocation defined for the frequency bands of the respective symbol transmission channel, wherein
modulation of a defined symbol transmission channel with a single symbol value is effected by up-converting a baseband shaped pulse signal to the frequency band of a respective symbol transmission channel which is allocated to a respective single symbol value.
2. A method according to claim 1, further comprising:
defining a usage order for modulating the defined symbol transmission channels; and
modulating each symbol transmission channel successively according to the defined usage order.
3. A method according to claim 1, wherein the defined symbol transmission channels are reused for effecting a modulation with symbol values of the digital message upon the number of symbols in the digital message exceeding the number of defined symbol transmission channels.
4. A method according to claim 3, wherein the defined symbol transmission channels are reused in the order used for modulating the defined symbol transmission channels with the first symbol values of the digital message.
5. A method according to claim 3 wherein the defined symbol transmission channels are reused in an order different to the order used for modulating the defined symbol transmission channels with the first symbol values of the digital message.
6. A method according to claim 1, wherein the bandwidth of the baseband shaped pulse signal corresponds to the bandwidth defined for the frequency band to which it is up-converted.
7. A method according to claim 1, wherein at least two sub-channels are defined for a frequency band of the set of frequency bands such that the phase angles of any two sub-channels defined for a frequency band are different.
8. A conversion controller for a frequency shift keying transmitter and for a frequency shift keying receiver, the controller comprising:
symbol transmission channel definition means for defining at least two symbol transmission channels with each symbol transmission channel being formed by a sub-set of frequency bands selected from a set of frequency bands;
allocation means for allocating each frequency band of a symbol transmission channel to a symbol value of the set of symbol values in a one-to-one relation such, that the symbol transmission channels differ from each other in at least one frequency band of the sub-set of frequency bands andor in an allocation of a frequency band to a symbol value; and
output means for outputting a control signal to an oscillator, whereby the control signal is adapted to adjust the oscillator frequency to the centre frequency of the frequency band used for modulating a respective symbol transmission channel, wherein
the symbol transmission channel definition means further comprises a sub-channel definition means for defining at least two sub-channels with different phase angles for each frequency band, and
the output means is further adapted to control a phase of an oscillator according to the phase angle defined for a sub-channel.
9. A transmitter having a conversion controller according to claim 8.
10. A frequency modulation method for imprinting a digital message formed by a sequence of symbols on a set of frequency bands, whereby each symbol is assigned one symbol value out of a defined set of symbol values, the method comprising:
defining at least two symbol transmission channels formed by a sub-set of frequency bands selected from the set of frequency bands, each frequency band of each symbol transmission channel within one time frame being allocated to a symbol value of the set of symbol values in a one-to-one relation, such that the symbol transmission channels differ within one time frame from each other in at least one frequency band of the sub-set of frequency bands andor in an allocation of a frequency band to a symbol value;
modulating each of the defined symbol transmission channels successively with a single symbol value of the digital message according to the allocation defined for the frequency bands of the respective symbol transmission channel;
rotating the allocation of the frequency bands to the symbol values for each time frame; and
rotating the allocation of the frequency bands from frame to frame in such a way that a fixed frequency offset between the frequency band of a symbol transmission channel in a current time frame and the corresponding frequency band used in the corresponding symbol transmission channel of the previous time frame is achieved, wherein
at least two sub-channels are defined for a frequency band of the set of frequency bands such that the phase angles of any two sub-channels defined for a frequency band are different.
11. A conversion controller for a frequency shift keying transmitter and for a frequency shift keying receiver, the controller comprising:
symbol transmission channel definition means for defining at least two symbol transmission channels with each symbol transmission channel being formed by a sub-set of frequency bands selected from a set of frequency bands;
allocation means for allocating within one time frame each frequency band of a symbol transmission channel to a symbol value of the set of symbol values in a one-to-one relation such that the symbol transmission channels within one time frame differ from each other in at least one frequency band of the sub-set of frequency bands andor in an allocation of a frequency band to a symbol value; and
output means for outputting a control signal to an oscillator, whereby the control signal is adapted to adjust the oscillator frequency to the centre frequency of the frequency band used for modulating a respective symbol transmission channel, wherein
the allocation means rotates the allocation of the frequency bands to the symbol values for each time frame and rotates the order of the frequency bands from frame to frame in such a way that a fixed frequency offset between the frequency band of a symbol transmission channel in a current time frame and the corresponding frequency band used in the corresponding symbol transmission channel of the previous time frame is achieved, and
the symbol transmission channel definition means includes sub-channel definition means for defining at least two sub-channels with different phase angles for each frequency band.