# Multiply 1Hz timebase

A

#### Al Klein

Jan 1, 1970
0
Is it possible to selectivley multiply a 1Hz timebase by whole
integers, ie. 2,3,4,5 ... Hz? If so, what would be the simplest way,
without using a microprocessor, PIC, etc.

Al Kein

J

#### John Popelish

Jan 1, 1970
0
Al said:
Is it possible to selectivley multiply a 1Hz timebase by whole
integers, ie. 2,3,4,5 ... Hz? If so, what would be the simplest way,
without using a microprocessor, PIC, etc.

Al Kein
If you have time to wait for a control loop to settle, you
divide a voltage dependent oscillator by those integers and
phase lock the divided clock to the 1 Hz reference.

A CD4046 chip would do the phase lock:
http://xtronics.com/kits/ccode.htm

P

#### Phil Hobbs

Jan 1, 1970
0
John said:
If you have time to wait for a control loop to settle, you divide a
voltage dependent oscillator by those integers and phase lock the
divided clock to the 1 Hz reference.

A CD4046 chip would do the phase lock:
http://xtronics.com/kits/ccode.htm

How evenly spaced do you need the pulses to be, and how long a startup
time is acceptable? Direct phase locking will work just great if you
can wait a long time (a minute or thereabouts) for the loop to settle
down, or if you can stand very unequally spaced pulses, in which case
you can acquire lock in one cycle.

Cheers,

Phil Hobbs

A

#### Al Klein

Jan 1, 1970
0
How evenly spaced do you need the pulses to be, and how long a startup
time is acceptable? Direct phase locking will work just great if you
can wait a long time (a minute or thereabouts) for the loop to settle
down, or if you can stand very unequally spaced pulses, in which case
you can acquire lock in one cycle.

Cheers,

Phil Hobbs

I would prefer even spaced pulses, even if it takes a minute. Can you
point me to a suitable circuit?

I am a bit short on resource materials here, and could find nothing
sufficiently explicit online.

Starting with 1Hz, what is the highest practical frequency that can be
obtained without a range selector?

Many thanks,

Al Klein

R

#### rebel

Jan 1, 1970
0
Starting with 1Hz, what is the highest practical frequency that can be
obtained without a range selector?

There is no practical limit - some people phase lock a 10MHz oscillator to a 1Hz
referecne - but jitter/phase_noise will increase as the multiplier.

Replies
2
Views
1K
C
Replies
7
Views
9K
MooseFET
M
L
Replies
11
Views
10K
Don Bowey
D
R
Replies
7
Views
4K
randomname
R
G
Replies
10
Views
2K
Ken Smith
K