JPS62100664A - Waveform display unit - Google Patents

Abstract

PURPOSE:To enable increase in the number of main scanning lines, by making the main scanning direction of a display unit vertical to allow the pulses synchronizing the main scanning to be counted with an address counter. CONSTITUTION:A raster scan type display unit 21 is raster scanned over a display surface thereof with a control unit 22. Pulses synchronizing a main scanning from an terminal 24 of the control section 22 are inputted into an address counter 25 to count. With counts of the counter 25 as address, a waveform memory 27 is read out, the output is latched with a latch circuit 28, the output of which is transferred to a latch circuit 29. Respective output data of the circuits 28 and 29 are preset on counters 31 and 32 by the pulse synchronizing the main scanning and the counters 31 and 32 decrementally count dot clocks of individual dot clock generators 23. An output of the counter 31 is fed to a display signal input terminal 34 through an OR circuit 33. Outputs of the counters 31 and 32 are inputted into respective FFs 36 through a selector 35. On the other hand, output data of the circuits 28 and 29 are compared by a comparator 37 to control the selector 35 according to the output thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a waveform display device used, for example, in a display of a spectrum analyzer.

[Conventional technology]

In a conventional waveform display device of this kind, at each point on the main scanning (horizontal scanning) of the display, each point of the waveform to be displayed is assigned the number of the main scanning line, number, or number of the sub-scanning (vertical scanning). It is stored in the waveform memory as data indicating which position is present, and for each main scan, all addresses of the waveform memory are sequentially read out every dot clock, and the read data and the number of the main scanning line at that time are stored. (position on the sub-scan), a waveform display signal was obtained at 7.

In this conventional waveform display device, each point on the main scan corresponds to each address in the waveform memory, so it is necessary to read all addresses in the waveform memory for each main scan, which increases the display resolution. In order to obtain the waveform memory address, it is necessary to increase the number of dots in one main scanning line and increase the number of waveform memory addresses to be output during one main scanning period. A high-speed counter is required as the address counter, a high-speed waveform memory is required, and a comparator that compares the position on the sub-scan with the read data for each dot must also be capable of high-speed operation. However, the whole thing is expensive.

When a standard cathode ray tube display is used as a display, its main scanning frequency is 16 kHz and sub-scanning frequency is 60 Hz.
If the resolution in the main scanning direction is 1000 points (pixels), each pixel is displayed at 16 MHz (dot clock frequency). At this time, the resolution in the sub-scanning direction, that is, the number of main scanning lines, is 500 or less. To double the resolution in the sub-scanning direction, if the main scanning frequency is doubled and the resolution in the main scanning direction remains at 1000 points, the dot clock will be 32 MHz. Furthermore, if the resolution in the main scanning direction is doubled to 2000 points, the frequency of the dot clock becomes 64 MHz.

Even if the frequency of the dot clock is 32 MHz, the access time of the single-skin type memory is as fast as 25 nanoseconds, and an emitter-coupled-knock (ECL) memory is required, making it expensive and consuming more power. The performance of the comparator is also required to be able to compare 10 bit data in 30 nanoseconds or less.

From these points of view, there is a limit to the ability of conventional waveform display devices to improve waveform quality by increasing the number of dots in the main scan.

[Means for solving problems]

According to the present invention, when the main scanning direction of the display device was conventionally horizontal, it is now the vertical direction, main scanning synchronizing pulses are counted by an address counter, and the waveform memory is read by the address counter. The dot clocks are counted for each main scanning synchronization pulse, and when a number corresponding to the data read from the waveform memory is counted, a first detection output is output. Further, dot clocks are counted for each main scanning synchronization/malus, and when the number of dot clocks corresponding to the data read from the waveform memory at the previous address is counted, a second detection output is output. The signal between one of the first detection output and the second detection output is supplied to the display device as a display signal,
The data read from the waveform memory and the data read from the previous address are compared by a comparator, and depending on the comparison result, either the first detection output or the second detection output is set as the leading edge of the display signal. This control is carried out.

Because of this structure, the waveform memory only needs to be read out at the speed of the main scanning intaglio clock, rather than the dot clock.
As the waveform memory, one that operates slower than the conventional one can be used.

〔Example〕

FIG. 1 shows the state of rask scanning on the display surface of the display device used in the device of this invention. In conventional displays, the main scanning direction is generally the horizontal direction, but when displaying the same waveform in the same orientation as in the past, in this invention the direction of the main scanning lineman 1 is the vertical direction. It is said that

FIG. 2 shows an embodiment of a waveform display device according to the present invention.

The display surface of the rask scanning type display 21 is raster scanned by the control section 22 as shown in FIG.

The control section 22 receives the dot clock from the dot clock generator 23, and uses this as a reference to generate the main scanning synchronization pulse, sub-scanning synchronization, and so on. The display surface of the display 21 is scanned in synchronization with these synchronization pulses.

A main scanning synchronizing pulse is input from the terminal 24 of the control section 22 to the address counter 25 and counted.

The address counter 25 is reset by the sub-scanning synchronization pulse from the terminal 26 of the control section 22. The waveform memory 27 is read using the count value of the address counter 25 as an address. The waveform memory 27 stores data indicating the position of the display waveform on each main scanning line. The data read from the waveform memory 27 is latched by the latch circuit 28 by the main scanning synchronizing pulse, and the output of the latch circuit 28 is transferred to the latch circuit 29. The output data Dn and Dm of the latch circuits 28 and 29 are respectively preset in counters 31 and 32 by main scanning synchronizing pulses, and the counters 31 and 32 count down the dot clock of the dot clock generator 23, respectively. Therefore, when the pad clock (only data Dn) is counted, a down-digit output is generated from the counter 31, and data Dn is also counted.
When m dot clocks are counted, the counter 32 generates a carry down output.

The output of the counter 31 is supplied as a display signal to a display signal input terminal 34 of the display 21 through an OR circuit 33.

In addition, each output of the counters 31 and 32 is connected to the selector 3.
5 are all input to flip-flop f36. on the other hand,
The respective output data Dn and Dm of the latch circuits 28 and 29 are compared by a comparator 37, and the selector 35 is controlled by the comparison output.

With this configuration, when the waveform memory 27 is read out at the beginning of each main scan and the dot clocks are counted for the read data, a bright spot is generated at that scanning position on the main scanning line. .

That is, by the output of the counter 31, one bright spot is generated on each main scanning line, for example, as shown by mark 8 in FIG. 3, in accordance with the data read from the waveform memory.

Further, if the comparison result in the comparator 37 is Dn>Dm, the slope of the displayed waveform is positive, and in the example of FIG. D
m>Dn, the selector 35 is in the state shown by the solid line, the flip-flop 36 is set by the output of the counter 32, and is reset by the counter 31. That is, when the fifth main scanning line starts and two dot clocks are counted, the flip-flop 36 is set by the output of the counter 32, its output becomes high level, and the third
As shown in the figure, a bright spot appears as a mark, and when nine dot clocks are counted, the flip-flop 36 is reset by the output of the counter 31 and the brightness ends at a low level. In the sixth main scanning line, Dn=3 and Dm=9, and when Dn<Dm, the selector 35 becomes a dotted line state. Therefore, when three dot clocks are counted, a bright spot is generated by the output of the counter 31, and the flip-flop 36 is set, and when nine dot clocks are counted, the counter 32
The flip-flop 36 is reset by the output of , and the bright spot aperture disappears.

"Effects of the Invention" As described above, according to the present invention, the waveform memory 27 only needs to be read out every main scanning synchronization pulse, and the access time is significantly reduced compared to the conventional case where it is read out every dot clock. Therefore, the number of main scanning lines can be easily increased to increase resolution. Further, the comparison operation of the comparator 37 may be performed at a low speed as long as it is performed in the main scanning period. Therefore, according to the present invention, there is no need to use an ECL circuit even when the resolution is high, and it is possible to use inexpensive devices as the waveform memory 27 and the comparator 37, and the power consumption is low. The counters 31 and 32i may be used as associative counters, and may be used as complements to the number of dots of one main scanning line of data stored in the waveform memory 37.

The selector 35 may be omitted and the Q output and the mutual output of the flip-flop 7' 36 may be selected in accordance with the output of the comparator 37 and supplied to the OR circuit 33.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a rask scan of the display surface of a display device used in the present invention, FIG. 2 is a block diagram showing an example of a waveform display device according to the present invention, and FIG. 3 is a diagram showing a display state for explaining its operation. FIG. 21: Display, 22: Control unit, 2.1: Main scanning synchronization terminal, 25 Near address counter, 26: Sub-scanning synchronization terminal? Lux output Mizuko, 27: Waveform memory, 28, 2
9: launch circuit, 31, 32: counter, 35: selector, 36: flip-flop.

Claims (1)

[Claims] (1) An address counter that is reset by a sub-scanning synchronization pulse and counts main-scanning synchronization pulses, a waveform memory that is addressed and read out according to the contents of the address counter, and data read out from the waveform memory. a comparator that compares the data read at the previous address; and a first detection means that counts dot clocks for each of the main scanning synchronization pulses and detects that the number of dot clocks corresponding to the read data has been counted. Then, count the dot clocks for each main scanning synchronization pulse mentioned above,
a second detection means for detecting that a number corresponding to the read data at an address immediately before the read data has been counted; set by the detection output of one of the first detection means and the second detection means; a flip-flop reset by the other detection output; means for inverting the output polarity of the flip-flop in accordance with the output of the comparator; the output of the flip-flop being supplied as a display signal; A waveform display device comprising a scanning display whose display surface is main-scanned and sub-scanned in synchronization with a sub-scan synchronizing pulse.