Radio signal generator
View Patent ↗A signal generator includes a memory for storing content information in the form of vectors including in-phase and quadrature elements of an orthogonal frequency division multiplexing waveform, a processor for converting the vectors to a radio frequency signal, and a logic device for controlling the operation of the memory and the processor. The in-phase and quadrature elements represent baseband content of the orthogonal frequency-division multiplexing waveform.
1. A signal generator comprising:
a memory for storing content information in the form of vectors including in-phase and quadrature elements of a digital representation of the content that is used to modulate an orthogonal frequency division multiplexing waveform;
a signal processor for converting the stored vectors to a first radio frequency signal;
a first filter for extracting an AM in-band on-channel signal from the first radio frequency signal;
a mixer for mixing the first radio frequency signal with a reference signal to produce a second radio frequency signal;
a second filter for extracting an FM in-band on-channel signal from the second radio frequency signal; and
a control processor for controlling the operation of the memory and the signal processor, wherein the in-phase and quadrature elements represent baseband content of the first radio frequency signal.
2. The signal generator of claim 1 , wherein the
FM in-band on-channel signal comprises an analog modulated carrier and a plurality of digitally modulated sub-carriers.
3. The signal generator of claim 2 , wherein the
AM in-band on-channel signal comprises an analog modulated carrier and a plurality of digitally modulated sub-carriers.
4. The signal generator of claim 1 , wherein the memory is removable.
5. The signal generator of claim 1 , wherein the memory is updatable through a data port.
6. The signal generator of claim 1 , further comprising:
a battery for powering the signal processor and control processor.
7. A signal generator comprising:
a memory for storing content information in the form of vectors including in-phase and quadrature elements of a digital representation of content that is used to modulate an orthogonal frequency division multiplexing waveform;
a signal processor for converting the stored vectors to a first radio frequency signal;
a filter for extracting an AM in-band on-channel signal from the first radio frequency signal;
a mixer for mixing the first radio frequency signal with a reference signal to produce a second radio frequency signal;
a filter for extracting an FM in-band on-channel signal from the second radio frequency signal; and
a control processor for controlling the operation of the memory and the signal processor, wherein the vectors represent a signal of interest and are encoded to include one or more of noise, fading, and an interfering signal, and wherein the in-phase and quadrature elements represent baseband content of the first radio frequency signal.
8. The signal generator of claim 7 , wherein the power ratio of the signal of interest and the interfering signal is adjustable.
9. The signal generator of claim 7 , wherein the interfering signal represents a first adjacent interferer.
10. The signal generator of claim 1 , wherein the vectors represent an integral number of transfer frames in a broadcast signal.
11. The signal generator of claim 1 , further comprising:
a user interface for controlling the control processor.
12. A method of demonstrating or testing the operation of a radio receiver, the method comprising the steps of:
using a portable signal generator to produce a first radio frequency signal,
wherein the portable signal generator includes a memory containing vectors including in-phase and quadrature elements used to produce the first radio frequency signal,
a filter for extracting an AM in-band on-channel signal from the first radio frequency signal, a mixer for mixing the first radio frequency signal with a reference signal to produce a second radio frequency signal, and
a filter for extracting an FM inband on-channel signal from the second radio frequency signal, and wherein the vectors represent a signal of interest and are encoded to include one or more of noise, fading, and an interfering signal, and wherein the in-phase and quadrature elements represent baseband content of the radio frequency signal;
transmitting the AM in-band on-channel signal and the FM in-band on-channel signal to a radio receiver; and
using the radio receiver to produce an output in response to the AM in-band on-channel signal or the FM in-band on-channel signal.
13. The method of claim 12 , wherein the power ratio of the signal of interest and the interfering signal is adjustable.
14. The method of claim 12 , wherein the interfering signal represents a first adjacent interferer.
15. The method of claim 12 , wherein the vectors represent an integral number of transfer frames in a broadcast signal.
16. A signal generator comprising:
an input for receiving analog content information;
an analog-to-digital converter for converting the analog content information to digital content information;
a first processor for converting the digital content information to a plurality of vectors including in-phase and quadrature elements;
a second processor for processing the vectors to produce a first radio frequency signal;
a filter for extracting an AM in-band on-channel signal from the first radio frequency signal;
a mixer for mixing the first radio frequency signal with a reference signal to produce a second radio frequency signal; and
a filter for extracting an FM in-band on-channel signal from the second radio frequency signal, wherein the in-phase and quadrature elements represent baseband content of the first and second radio frequency signals.
17. The signal generator of claim 16 , wherein the
FM in-band on-channel signal comprises an analog modulated carrier and a plurality of digitally modulated sub-carriers.
18. The signal generator of claim 17 , wherein the
AM in-band on-channel signal comprises an analog modulated carrier and a plurality of digitally modulated sub-carriers.
19. The signal generator of claim 16 , wherein the vectors represent a signal of interest and an interfering signal.
20. The signal generator of claim 19 , wherein the power ratio of the signal of interest and the interfering signal is adjustable.
21. The signal generator of claim 19 , wherein the interfering signal represents a first adjacent interferer.
22. The signal generator of claim 16 , wherein the vectors represent an integral number of transfer frames in a broadcast signal.