Polar coordinate display device employing raster scan scheme

Details Polar coordinate display device employing raster scan scheme Polar coordinate display device employing raster scan scheme

1986-12-01

1988-10-25

Caldwell, Sr., John W.

Communications: electrical

Land vehicle alarms or indicators

Internal alarm or indicator responsive to a condition of the...

340799, G09G 102

Patent

active

047807121

DESCRIPTION:

BRIEF SUMMARY
[TECHNICAL FIELD]

The present invention relates to a polar coordinate display device employing a raster scan scheme and, more particularly, to an improved polar coordinate display device which can display, as a vector, measurement data which is supplied from a signal analyzer such as a network analyzer, as a polar coordinate graph without discontinuity, in a real time manner, on an image display unit employing a raster scan scheme.


[BACKGROUND ART]

As is well known, measurement data such as transmission characteristics analyzed or measured by a network analyzer, or an impedance which is analyzed or measured by an impedance analyzer, is given as a vector defined by an amplitude and a phase. When the measurement data expressed by such a vector is converted into polar coordinates and displayed as an image, whose amplitude and phase can be read from a single curve of a graph. In this case, it is convenient to use an image display unit employing a raster scan scheme. This is because a conventional image display unit (CRT display), represented by a television monitor, can be used.
FIG. 4 shows a conventional polar coordinate display device employing the raster scan scheme. For example, microprocessor 2 in signal analyzer 1, such as a network analyzer, converts vector data analyzed by signal analyzer 1 into polar coordinates, and sets the polar coordinate data and address data for image memory 4, which stores the polar coordinate data in graphic display controller 3 via data and address buses DB and AB. Graphic display controller 3 sets, in image memory 4, address data therefor set by microprocessor 2, and writes graph data (to be described later), based on the polar coordinate data converted by microprocessor 2, at a set address of image memory 4. Image memory 4 has a memory format having a one-to-one correspondence to the screen display format of image display unit 8 of a raster scan scheme such as a CRT. Graphic display controller 3 reads out data of image memory 4 by a timing pulse generated by timing circuit 7 in synchronism with raster scan by image display unit 8. In this case, a write-in cycle and a read-out (raster scan) cycle, in accordance with which graphic display controller 3 accesses image memory 4, are executed in a time divisional manner. Parallel-bit data read out from image memory 4 is converted into serial-bit data in parallel-serial converter 5 by a timing pulse generated by timing circuit 7. The serial-bit data is converted into a video signal via video circuit 6 and supplied to image display unit 8, so that the vector data analyzed by signal analyzer 1 is displayed as a graph curve of polar coordinate data.
When the vector data analyzed or measured by signal analyzer 1 is displayed in a real time manner to correspond to measurement scan, the graph of the coordinates which corresponds to the respective measurement point, i.e., previous graph data written in image memory 4, must be deleted, while displaying new data on the same coordinate system.
FIG. 5 shows an orthogonal coordinate system wherein a measurement scan direction and a graph display direction (to be referred to as a trace direction hereinafter) are the same, and the pitch of graph display (to be referred to as a trace hereinafter) is constant. In this case, no inconvenience occurs when the previous data is deleted and the new data is displayed in the case described above. This is because a graph of new point P in the measurement scan direction can be displayed by deleting data of the graph on point P from an image memory and writing new data in the image memory.
In contrast to this, FIG. 6 shows a polar coordinate system wherein a horizontal direction is expressed by X=Acos.theta. and a vertical direction is expressed as .gamma.=Asin.theta.. In this case, a measurement scan direction and a graph trace direction are generally different. In polar coordinate representation, the pitch of the graph trace is different from that of orthogonal coordinate representation, and is not constant. For this reason, when the vector data anal

REFERENCES:
patent: 4200869 (1980-04-01), Murayama et al.

Affiliated with

Also associated with

Rating

Polar coordinate display device employing raster scan scheme does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Polar coordinate display device employing raster scan scheme, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polar coordinate display device employing raster scan scheme will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2271840