A television signal encoder for luminance and chrominance signals presented in digital form comprises luminance and chrominance channels in which the blanking and color burst signals are inserted digitally before the signals are converted to analogue form for modulation and transmission. The luminance signal is presented to a buffer circuit (2) and during the line period the output of the buffer circuit (2) is fed to a DAC (6) via a highway (5) under the control of an enable signal. During the blanking period a ROM (26) applies a digital version of the blanking level to the highway (5). A ROM (3) is enabled for a short period at the start and finish of the blanking period and is arranged as a variable multiplier to determine the slope of the blanking waveform. The output of the DAC (6) is filtered (8) and it is added to the modulated color subcarrier signal and the synchronizing pulse. The chrominance channel is basically similar to the luminance channel but includes means for demultiplexing the U and V signals and a further ROM for inserting the color burst amplitude. The U and V signals after filtering are fed to modulators to modulate the color subcarrier signal.

A method of controlling an image memory system wherein non-interlace image data is written into the odd field and the even field memories, and the contents written into the odd field and even field memories are respectively read out so as to be converted into interlace image data. Each line of the non-interlace image data is alternately written into the odd field and even field memories in units of a plurality of dots. If the plurality of dots include dots for the odd field and dots for the even field, the image data of the plurality of dots are simultaneously written into both the odd field memory and the even field memory. When reading the image data out from the odd field memory, the image data for the even field written into the odd field memory is invalidated. Similarly, when reading the image data out from the even field memory, the image data for the odd field written into the even field memory is invalidated. With this structure, writing/reading operation to the image memory can be performed at high speed without error even when the total number of dots on one line are not divisible by the number of dots to be written into the memories in parallel. Further, it is not necessary to change the output specification of the output device which outputs the image data, such as a computer.

A system (100) and method for outputting data from a detector (104). The novel system (100) includes a first controller (118) that samples the detector (104) at a first rate, a memory (112) for storing the sampled data, and a second controller (120) that outputs data from the memory (112) at a second rate. In a illustrative embodiment, the first rate is symmetrical from field to field, while the second rate is asymmetrical from field to field.

Circuitry for displaying a constantly changing M-mode transducer scan output on a raster scan display in the form of a first multiplicity of data lines each containing a second multiplicity of data words and each representing a scan of the transducer output at a particular closely spaced scanning time and such that the data line representing the oldest scan is periodically erased and a data line representing the newest scan is displayed. The circuitry includes random access memory having a first multiplicity of memory elements each for storing a data line. A random access memory input counter enables loading of the memory, data line by data line, and a random access memory advance output counter enables read out from the memory sequentially one data word from each line for each raster scan.

The present invention is a random accessible signal filing system containing magnetic discs, at least two buffer memories and a circuit for controlling the buffer memories in such a way that the write-in and read-out of at least two of the buffer memories may be alternately performed, whereby through random access, the required signals are selected and read out so as to be outputted as a series of signals. In this system, during the outputting of the signals, the signals coming from the magnetic discs are written into one of the buffer memories sector by sector at the read-out speed of the magnetic discs, and thereafter, are read out at the demodulating speed of the demodulator. The two buffer memories are so controlled that while the signals are written into one of them; the signals are read out from the other.