Traveling-message display system

Claim 1

In a traveling-message display system wherein information for display is supplied Thereto at a first variable rate subject to sudden starts and stops and wherein this information is displayed as characters on an array of neon lamps arranged in rows and columns, said characters being formed, one column at a time, on the extreme right-hand column of the array and being moved at a second variable rate from right to left thereacross, the second rate not being subject to sudden starts and stops, the averages of said two rates being equal, in combination: a buffer having a first state at which information supplied thereto is recirculated therethrough at a selected fixed speed and having a second state at which information is stored statically therein, said buffer being normally in the first state and being placed in the second state only in the presence of shift pulses, said buffer having a storage capacity in excess of that required by the array; a shift register having a like array of storage elements arranged into like rows and columns, each element being coupled to a corresponding lamp, information being supplied to the extreme right-hand column of elements in the register and being shifted column by column therethrough under the control of said shift pulses, the information in the register being displayed on the array; first means coupled between said buffer and said register to supply information when the buffer is in the second state from the output of the buffer to the register for display by the array; a generator for producing pulses at a fixed recurrence frequency F; a divide-by-N counter, where N is a variable integer, coupled at its input to the generator, said counter yielding at its output a pulse train at a variable recurrence frequency F/N; second means coupled between the counter, buffer and register to supply said variable frequency pulse train as shift pulses at said variable frequency to the buffer and register, thereby determining said second rate; and third means coupled between the buffer and the counter and enabled when the buffer is in the second state to produce a digital signal which varies with the amount of information stored in the buffer, said signal being supplied to said counter to determine the value of N.