Digital image signal processing circuits

A digital image signal processing circuit for use in an image pickup and recording apparatus containing an image pickup portion and a video signal recording portion, the circuit comprising:

• signal input terminal means to which an image pickup output signal obtained from the image pickup portion and a video signal supplied from the outside are selectively supplied,
• analog to digital converting means for digitizing one of the image pickup output signal and the video signal supplied to the signal input terminal means to produce one of a digital image pickup output signal and a digital video signal,
• digital signal processing means including first, second and third digital signal processing circuit blocks to which one of the digital image pickup output signal and the digital video signal is supplied,
• system controller means provided in common to said first, second and third digital signal processing circuit blocks for conducting selectively the change of operation, the change of circuit configuration and the change of circuit coefficient in each of said first, second and third digital signal processing circuit blocks in response to the selective supply of one of the image pickup output signal and the video signal to the signal output terminal means, and
• signal output terminal means from which a recording luminance signal and a recording chrominance signal which are produced by the digital signal processing means are derived, wherein:
• the first digital signal processing circuit block is operative to produce separately first digital luminance and chrominance signals based on the digital image pickup output signal and to cause the first digital luminance signal to be subjected to vertical aperture correction when the image pickup output signal is supplied to the signal input terminal means, and to produce second digital luminance and chrominance signals based on the digital video signal and to work on the second digital chrominance signal as a comb filter when the video signal is supplied to the signal input terminal means;
• the second digital signal processing circuit block is operative to function as a matrix circuit for the first digital chrominance signal when the image pickup output signal is supplied to the signal input terminal means and to function as a decoding circuit for the second digital chrominance signal when the video signal is supplied to the signal input terminal means;
• and
• the third digital signal processing circuit block is operative to function as an encoding circuit for the first digital chrominance signal when the image pickup output signal is supplied to the signal input terminal means and to produce a digital frequency-converted carrier chrominance signal having its carrier frequency converted to a lower frequency on the basis of the second digital chrominance signal when the video signal is supplied to the signal input terminal means.