Signal generator with display unit

• US 7,480,328 B2
• Filed: 04/30/2002
• Issued: 01/20/2009
• Est. Priority Date: 05/18/2001
• Status: Active Grant

• Current Assignee: Rohde & Schwarz GmbH & Company KG
• Original Assignee: Rohde & Schwarz GmbH & Company KG
• Inventors: Pauly, Andreas, Braunstorfinger, Thomas
• Primary Examiner(s): Fan; Chieh M
• Assistant Examiner(s): Fotakis; Aristocratis
• Application Number:
  US10/477,940
• Publication Number:
  US 20040184554A1
• Time in Patent Office: 2,457 Days
• Field of Search: 375/224, 375/227, 375/228, 375/295, 375/296, 702/66, 702/67, 702/68, 702/69, 702/127, 455/67.11, 455/67.14, 455/67.7
• US Class Current: 375/224
• CPC Class Codes: H04B 17/23 Indication means, e.g. displays, alarms, audible means

Abstract

A signal generator includes a baseband unit, generating a digital, and an I/Q modulator, modulating the digital baseband signal. A storing memory stores a time slot of said digital baseband signal and an optical display unit represents the digital baseband signal stored in said memory according to a predetermined representation mode.

Claims

1. A signal generator comprising:

a baseband unit configured to generate a digital baseband signal;

an I/Q modulator configured to modulate the digital baseband signal;

a recording memory configured to record a time segment of the digital baseband signal in a state prior to modulation by the I/Q modulator;

at least one or more signal modification units provided between the baseband unit and the I/Q modulator, wherein the signal at the input and output of each signal modification unit is routed via switching devices to the recording memory without further modification of each signal between each signal modification unit and the recording memory;

a visual display device configured to display the digital baseband signal stored in the recording memory in a predeterminable display mode, wherein the visual display device is configured to display the digital baseband signal in the state prior to modulation by the I/Q modulator,

wherein an I input of the recording memory can be connected via a first switching device and a Q input of the recording memory can be connected via a second switching device having a plurality of positions in the signal path of the I component or the Q component;

a plurality of decimation units coupled to the recording memory and configured to decimate the data stream of the digital baseband signal,

wherein a third switching device is coupled between a first one of the decimation units and the I input of the recording memory, and a fourth switching device is coupled between a second one of the decimation units and the Q input of the recording memory.

2. A signal generator according to claim 1, wherein one of the signal modification units is a noise unit and/or a fading unit and/or a distortion unit.

3. A signal generator according to claim 1, wherein the baseband unit has at least one sampling rate converter (resampler) and the signal at the input and/or output of each sampling rate converter can be routed to the recording memory.

4. A signal generator according to claim 1, wherein the baseband unit has at least one pulse-shaping filter and the signal at the input and/or output of each pulseshaping filter can be routed to the recording memory.

5. A signal generator according to claim 4, wherein the code-domain power of a CDMA signal is displayed on the display device and a symbol clock rate signal upstream of the pulse-shaping filter is routed to the recording memory.

6. A signal generator according to claim 1, wherein the start of the time segment that the recording memory records is controlled by a trigger signal (TS).

7. A signal generator according to claim 6, wherein the trigger signal (TS) is chosen in such a way that a plurality of time segments can be joined seamlessly to one another.

8. A signal generator according to claim 6, wherein the trigger signal (TS) is chosen in such a way that the time segments each cover periodic segments of a periodic baseband signal.

9. A signal generator according to claim 6, wherein the third switching device is further coupled between a third one of the decimation units and the I input of the recording memory to provide selection between the first decimation unit and the third decimation unit, and the fourth switching device is further coupled between a fourth one of the decimation units and the Q input of the recording memory to provide selection between the second decimation unit and the fourth decimation unit.

10. A signal generator according to claim 9, wherein the first decimation unit and the third decimation unit have different decimation factors, and the second decimation unit and the fourth decimation unit have different decimation factors.

11. A signal generator according to claim 1, wherein plural signal modification units are provided between the baseband unit and the I/Q modulator, and wherein the signal modification units are connected in series.

21. A signal generator according to claim 11, wherein the signal modification units include a fading unit and a noise unit.

12. A signal generator comprising:

a baseband unit configured to generate a digital baseband signal;

an I/Q modulator configured to modulate the digital baseband signal;

a recording memory configured to record a time segment of the digital baseband signal in a state prior to modulation by the I/Q modulator;

a visual display device configured to display the digital baseband signal stored in the recording memory in a predeterminable display mode, wherein the visual display device is configured to display the digital baseband signal in the state prior to modulation by the I/Q modulator; and

one or more signal modification units provided between the baseband unit and the I/Q modulator, wherein the signal at the input and output of each signal modification unit is routed via switching devices to the recording memory without further modification of each signal between each signal modification unit and the recording memory.

13. A signal generator according to claim 12, wherein an I input of the recording memory can be connected via a first switching device and a Q input of the recording memory can be connected via a second switching device having a plurality of positions in the signal path of the I component and the Q component, respectively, and wherein the plurality of positions in the signal path are upstream of the I/Q modulator.

14. A signal generator according to claim 12, wherein the baseband unit has at least one sampling rate converter (resampler) and the signal at the input and/or output of each sampling rate converter can be routed to the recording memory.

15. A signal generator according to claim 12, wherein the baseband unit has at least one pulse-shaping filter and the signal at the input and/or output of each pulse-shaping filter can be routed to the recording memory.

16. A signal generator according to claim 15, wherein the code-domain power of a CDMA signal is displayed on the display device and a symbol clock rate signal upstream of the pulse-shaping filter is routed to the recording memory.

17. A signal generator according to claim 12, wherein the start of the time segment that the recording memory records is controlled by a trigger signal (TS).

18. A signal generator according to claim 17, wherein the trigger signal (TS) is chosen in such a way that a plurality of time segments can be joined seamlessly to one another.

19. A signal generator according to claim 17, wherein the trigger signal (TS) is chosen in such a way that the time segments each cover periodic segments of a periodic baseband signal.

20. A signal generator according to claim 12, further comprising a plurality of decimation units coupled to the recording memory and configured to decimate the data stream of the digital baseband signal.

22. A signal generator according to claim 12, wherein plural signal modification units are provided between the baseband unit and the I/Q modulator, and wherein the signal modification units are connected in series.

23. A signal generator according to claim 22, wherein the signal modification units include a fading unit and a noise unit.